PATENT DOCUMENT

Publication Number: US-10998657-B2
Application Number: US-201916565336-A
Country: US
Kind Code: B2

Title: Precious-metal-alloy contacts

Abstract:
Contacts that can be highly corrosion resistant, can be readily manufactured, and can conserve precious materials. One example can provide contacts having a layer of a precious-metal alloy to improve corrosion resistance. The precious-metal-alloy layer can be plated with a hard, durable, wear and corrosion resistant plating stack for further corrosion resistance and wear improvement. The resources consumed by a contact can be reduced by forming a bulk or substrate region of the contact using a more readily available material, such as copper or a material that is primarily copper based.

Claims:
What is claimed is: 
     
       1. A contact for a connector, the contact comprising:
 a substrate having a contacting portion and a beam; 
 a plurality of plating layers plated over the substrate; and 
 a protective layer over the plurality of plating layers, the protective layer over the beam and absent over the contacting portion, the protective layer comprising titanium dioxide particles suspended in a base material. 
 
     
     
       2. The contact of  claim 1  further having a surface-mount portion, wherein the protective layer is absent over the surface-mount portion. 
     
     
       3. The contact of  claim 1  wherein the base material consists essentially of an acrylic. 
     
     
       4. The contact of  claim 3  wherein the protective layer is formed by electrophoretic deposition. 
     
     
       5. The contact of  claim 3  wherein the substrate is one of niobium or tantalum. 
     
     
       6. The contact of  claim 3  wherein the substrate is formed primarily of copper. 
     
     
       7. The contact of  claim 3  wherein the plurality of plating layers comprises a leveling layer over the substrate, a support layer over the leveling layer, and a first adhesion layer over the support layer. 
     
     
       8. The contact of  claim 7  wherein for the beam of the contact, the plurality of plating layers further comprises a first top plate over the first adhesion layer and below the protective layer. 
     
     
       9. The contact of  claim 8  wherein for the contacting portion of the contact, the plurality of plating layers further comprises the first top plate over the first adhesion layer, a second adhesion layer over the first top plate, a barrier layer over the second adhesion layer, and a second top plate over the barrier layer. 
     
     
       10. The contact of  claim 9  wherein the first adhesion layer is formed of gold and the barrier layer comprises one of palladium, silver, silver-palladium, or silver-palladium-bismuth-tellurium, or silver palladium tellurium. 
     
     
       11. The contact of  claim 10  wherein the first and second top plate comprise one of copper, gold, rhodium-ruthenium, rhodium, gold-palladium, gold-cobalt, or gold-copper. 
     
     
       12. A contact for a connector, the contact comprising:
 a substrate having a first section and a second section; 
 a plurality of plating layers plated over the substrate; and 
 a protective layer over the plurality of plating layers, the protective layer over the first section of the contact and comprising impurities suspended in a base material, wherein the impurities increase an effective corrosion path length through the protective layer from a top surface of the protective layer to a top surface of the plurality of plating layers. 
 
     
     
       13. The contact of  claim 12  wherein the base material consists essentially of an acrylic and the impurities comprise titanium dioxide. 
     
     
       14. The contact of  claim 13  wherein the protective layer is formed by electrophoretic deposition. 
     
     
       15. The contact of  claim 13  wherein the substrate is one of niobium or tantalum. 
     
     
       16. The contact of  claim 13  wherein the contact is formed by stamping. 
     
     
       17. The contact of  claim 13  wherein the contact is formed by coining. 
     
     
       18. The contact of  claim 12  wherein the protective layer is absent over the second section. 
     
     
       19. The contact of  claim 18  further having a third section, wherein the protective layer is absent over the third section. 
     
     
       20. The contact of  claim 18  wherein the first section is a beam, the second section is a contacting portion, and the third section is a surface-mount portion. 
     
     
       21. A contact for a connector, the contact comprising:
 a substrate; 
 a first plurality of plating layers over the substrate, the first plurality of plating layers comprising rhodium-ruthenium; and 
 a second plurality of plating layers over first plurality of layers, the second plurality of plating layers comprising rhodium-ruthenium, 
 wherein the second plurality of plating layers is plated over a first section of the substrate and the second plurality of plating layers is absent over a second section of the substrate. 
 
     
     
       22. The contact of  claim 21  wherein the first section of the substrate is a contacting portion and the second section of the substrate is a beam. 
     
     
       23. The contact of  claim 22  further comprising a protective layer over the second section of the substrate, wherein the protective layer comprises titanium dioxide particles suspended in a base material, where the base material comprises an acrylic.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 15/464,051, filed Mar. 20, 2017, which claims the benefit of U.S. patent application Nos. 62/310,445, filed Mar. 18, 2016, 62/383,381, filed Sep. 2, 2016, and 62/384,120, filed Sep. 6, 2016; which are incorporated by reference. 
    
    
     BACKGROUND 
     Electronic devices often include one or more connector receptacles though which they may provide and receive power and data. Power and data can be conveyed over cables that include a connector insert at each end of a cable. The connector inserts can be inserted into receptacles in the communicating electronic devices. In other electronic systems, contacts on a first device can be in direct contact with contacts on a second device without the need for an intervening cable. In such systems, a first connector can be formed as part of the first electronic device and a second connector can be formed as part of the second electronic device. 
     The contacts in these various connectors may be exposed to liquids and fluids that can cause the contacts to corrode. For example, a user may purposely or inadvertently submerge an electronic device or a connector insert in a liquid. A user may spill a liquid or perspire on contacts on an electronic device or connector insert. This can cause one or more contacts to corrode, particularly where a voltage is present on the one or more contacts. This corrosion can impair the operation of the electronic device or cable and in severe cases can render the device or cable inoperable. Even where operation is not impaired, corrosion can mar the appearance of the contacts. Where the contacts are at the surface of an electronic device or at the surface of a connector insert on a cable, such corrosion can be readily apparent to a user and it may create a negative impression in the mind of a user that can reflect poorly on the device or cable and the device or cable&#39;s manufacturer. 
     Some of these electronic devices may be very popular and can therefore be manufactured in great numbers. Therefore, it may be desirable that these contacts be readily manufactured such that demand for the devices can be met. It may also be desirable to reduce the consumption of rare or precious materials. 
     Thus, what is needed are contacts that can be highly corrosion resistant, can be readily manufactured, and can conserve precious materials. 
     SUMMARY 
     Accordingly, embodiments of the present invention can provide contacts that can be highly corrosion resistant, can be readily manufactured, and can conserve precious materials. These contacts can be located at a surface of an electronic device, at a surface of a connector insert, in a connector insert on a cable, in a connector receptacle on an electronic device, or elsewhere in a connector system. 
     An illustrative embodiment of the present invention can provide connector contacts that include a layer or portion formed of a precious-metal alloy to improve corrosion resistance. The precious-metal-alloy layer can be plated for further corrosion resistance and wear improvement. Resources can be conserved by forming a bulk or substrate region of the contact using a more common material, such as copper or a material that is primarily copper based. The combination of a precious-metal alloy and a more common bulk or substrate region can provide contacts having both improved corrosion resistance and a lower overall precious resource consumption. 
     In these and other embodiments of the present invention, the precious-metal-alloy layer or contact portion can be formed of a high-entropy material. Examples of this material can include material consistent with ASTM Standards B540, B541, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer can be selected to have a good hardness and strength, as well as a high conductivity or low electrical resistance such that contact resistance is reduced. In various embodiments of the present invention, the precious-metal-alloy layer can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. A material having a good formability and high elongation for improved manufacturability can be selected for use as the precious-metal alloy. In these and other embodiments of the present invention, a precious-metal-alloy layer can have a thickness less than 10 micrometers, more than 10 micrometers, from 10 micrometers to 100 micrometers, from 10 micrometers to hundreds of micrometers, more than 100 micrometers, from 100 micrometers to hundreds of micrometers, or it can have a thickness in a different range of thicknesses. In these and other embodiments of the present invention, portions of, or all of a contact, can be formed of a precious-metal alloy. 
     In these and other embodiments of the present invention, the precious-metal-alloy layer can be clad over a substrate formed of a more common material, though in other embodiments of the present invention, portions of, or all of a contact, can be formed of a precious-metal alloy. This substrate can be formed using a material that is copper or copper based, such as phosphor bronze. In these and other embodiments of the present invention, the substrate can be formed using copper-nickel-tin, copper-nickel-silver alloy, steel, or other appropriate material or alloy. Material having good electrical conductivity and a good availability can be selected for use to form the contact substrate. The material can also be selected to have a good formability, elongation, and hardness that are similar to that of the material used for the precious-metal-alloy layer. In various embodiments of the present invention, the substrate layer can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. In these and other embodiments of the present invention, the bulk or substrate layer can form the majority of the contact and can have a thickness less than 1 mm, more than 1 mm, between 0.5 mm and 1.5 mm, approximately 1.0 mm, between 1 mm and 10 mm, more than 10 mm, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a diffusion or bonding layer can be formed when the precious-metal alloy is bonded or clad to the substrate. This bonding layer can be an intermetallic bond of the precious-metal alloy and the alloy of the substrate. This diffusion or bonding layer can be less than 1 micrometer, more than 1 micrometer, 1 to 5 micrometers, 5 micrometers, or more than 5 micrometers thick. 
     In these and other embodiments of the present invention, one or more intermediate layers can be placed between the precious-metal-alloy layer and the substrate. These intermediate layers can have better corrosion resistance than copper and can also be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers can be formed using titanium, steel, tantalum, or other material. This material can be selected based on its availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     In these and other embodiments of the present invention, the precious-metal-alloy layer can be plated with a hard, durable, wear and corrosion resistant plating stack. This stack can be formed of one or more plating layers. 
     A first plating layer can be plated over the precious-metal-alloy layer for leveling and adhesion. For example, gold, copper, or other material can act as a leveler and tend to fill vertical differences across a surface of the precious-metal-alloy layer. This can help to cover defects in the substrate, such as nodules or nodes that can be left behind by an electropolish or chemical polishing step. This first plating layer can also provide adhesion between the precious-metal-alloy layer and a second plating layer or top plate. Instead of gold or copper, the first plating layer can be formed of nickel, tin, tin copper, hard gold, gold cobalt, or other material, though in other embodiments of the present invention, the first plating layer can be omitted. This first plating layer can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.0.5 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a top plate can be plated over the first plating layer. The top plate can provide a durable contacting surface for when the contact on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, the top plate can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce its corrosion. The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. This top plate can have a thickness less than 0.5 micrometers, between 0.5 and 0.75 micrometers, between 0.75 and 0.85 micrometers, between 0.85 and 1.1 micrometers, more than 1.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, instead of a top plate being plated over the first plating layer, a second plating layer can be plated over the first plating layer. The second plating layer can act as a barrier layer to prevent color leakage from the precious-metal-alloy layer to the surface of the contact, and the material used for the second plating layer can be chosen on this basis. In these and other embodiments of the present invention, the second plating layer can be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material can provide a second plating layer that is more positively charged than a top plate of rhodium-ruthenium, rhodium, or other material. This can cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This second plating layer can have a thickness less than 0.1 micrometers, between 0.1 and 0.5 micrometers, between 0.5 and 1.0 micrometers, between 1.0 and 1.5 micrometers, more than 1.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the first plating layer can be omitted and the second plating layer can be plated directly on the precious-metal layer. 
     In these and other embodiments of the present invention, a third plating layer can be plated over the second plating layer. The third plating layer may, like the first plating layer, provide leveling and adhesion. For example, gold can tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and can provide adhesion between the second plating layer and a top plate. For example, a gold plating layer can provide adhesion between a second plating layer of palladium and a top plate of rhodium-ruthenium. The gold layer can be a plated gold strike. Instead of gold, the third plating layer can be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.05 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the third plating layer can be omitted and the top plate can be plated directly on the second plating layer. 
     In these and other embodiments of the present invention, the top plate described above can be plated over the third plating layer. 
     In these and other embodiments of the present invention, the plating materials used can be selected based a desire to conserve precious resources, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     These contacts can be formed in various ways in various embodiments of the present invention. In an illustrative embodiment of the present invention, a layer of precious-metal alloy can at least partially cover a layer of substrate material. As described herein, one or more intermediate layers can be placed between the layer of precious-metal alloy and the substrate. Contacts can be stamped such that a precious-metal-alloy layer can be clad to a bulk or substrate layer, or over the bulk or substrate layer with one or more intermediate layers. The materials used can be heated (and possibly annealed) and elongated during the stamping. For example, a 35, 50, or 70 percent elongation can be used. 
     In these and other embodiments of the present invention, carriers can be stamped of the bulk material. These carriers can be used to carry or otherwise manipulate the contacts during further manufacturing steps, such as blasting, polishing, sanding, plating (for example, as described herein), further annealing, or other process steps. 
     In these and other embodiments of the present invention, the layer of precious-metal alloy can be placed on a top surface of a layer of bulk or substrate material before stamping. In other embodiments of the present invention, one or more grooves can be formed in the layer of bulk or substrate material and the layer of precious-metal alloy can be placed in the one or more grooves. In these and other embodiments of the present invention, one or more of the grooves can be deeper than one or more of the remaining grooves. In this way a layer of precious-metal alloy in a contact can have a greater depth along at least a portion of the sides of the contact. This can help to improve corrosion resistance along sides of the resulting contacts. 
     In these and other embodiments of the present invention, contacts can be formed in other ways and have different plating layers. For example, strips of a copper alloy or other material can be butt-welded or otherwise fixed or attached to sides of a strip of a precious-metal alloy to form a strip or roll of material for stamping. Contacts can be stamped such that all of the contact is formed of the precious-metal alloy while a carrier is formed of the copper alloy or other material. Contacts can also be stamped such that only portions, such as a contacting portion, are formed of the precious-metal alloy while the remainder of the contact and a carrier can be formed of the copper alloy or other material in order to conserve resources. 
     These and other embodiments of the present invention can include various plating layers at a contacting portion or other portion of a contact. In one example a contact substrate can be stamped, for example from a sheet or strip of copper, or a strip that includes strips of copper welded to sides of a strip of a precious-metal alley. An electropolish step can be used to removing stamping burrs, which could otherwise expose nickel silicides or other particles in the substrate. Unfortunately, the electropolish step can leave nodules on the contact surface. Chemical polish can be used in its place, though that can leave nodes behind on the contact surface. 
     Accordingly, a first plating layer to provide a surface leveling can be plated on the substrate. This first plating layer can be copper or other material, such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, and it can be plated over the contact substrate to level the surface of the stamped substrate and cover nodules left by electropolishing or nodes left by chemical polishing as well as remaining burrs or other defects from the stamping process. In these other embodiments of the present invention, the first plating layer can be sufficient and an electropolish step can be omitted. The first plating layer can also provide adhesion between the substrate and a second plating layer that can be plated over the first plating layer. The first plating layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 4.5 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     Cracks in these plating layers can provide pathways for fluids that can cause corrosion. Accordingly, a second, harder plating layer to prevent layers above the second plating layer from cracking can be plated over the first plating layer. This second plating layer can be formed of an electroless nickel composite. This second plating layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 2.0 micrometers, 2.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. In various embodiments of the present invention, this second layer can be omitted. 
     A third plating layer can work in conjunction with the second plating layer. The third plating layer can be plated over the second plating layer. This third plating layer can be soft to absorb shock and thereby minimize cracking in the layers above the third plating layer. The third plating layer can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer can provide adhesion between its neighboring layers and can provide a leveling effect as well. This third plating layer can have a thickness of 0.55 to 0.9 micrometers, 0.5 to 1.25 micrometers, 1.25 to 2.5 micrometers, 2.5 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. In various embodiments of the present invention, these second and third plating layers can be omitted, or the second layer can be omitted, though other layers can be added or omitted as well. 
     A fourth plating layer to provide corrosion resistance can be plated over the third plating layer. The fourth plating layer can act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the fourth plating layer can be chosen on this basis. This layer can be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material can provide a second plating layer that is more positively charged than a top plate of rhodium-ruthenium, rhodium, or other material. This can cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer can be somewhat harder than a fifth plating layer above it, which can prevent layers above the fourth plating layer from cracking when exposed to pressure during a connection. The fourth plating layer can have a thickness of 0.5 to 0.8 micrometers, 0.5 to 1.0 micrometers, 1.0 to 1.5 micrometers, 1.5 to 3.0 micrometers, or more than 3.0 micrometers, or it can have a thickness in a different range of thicknesses. When palladium is used, it can be plated at a rate of 0.6 plus or minus 0.1 ASD or other appropriate rate. 
     A fifth plating layer to act as an adhesion layer between the fourth plating layer and a top plate can be plated over the fourth plating layer. The fifth plating layer can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The fifth plating layer can provide further leveling as well. The fifth plating layer can have a thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.10 to 0.20 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses. 
     A top plate can be formed over the fifth plating layer. The top plate can be highly corrosive and wear resistant. This layer can be thinned in high-stress locations to reduce the risk of cracking. The top plate can provide a durable contacting surface for when the contact on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, the top plate can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce its corrosion. The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate can have a thickness less than 0.5 micrometers, between 0.5 and 0.75 micrometers, between 0.65 and 1.0 micrometers, between 0.75 and 1.0 micrometers, between 1.0 and 1.3 micrometers, more than 1.3 micrometers, or it can have a thickness in a different range of thicknesses. 
     In various embodiments of the present invention, these layers can be varied. For example, the top plate can be omitted over portions of the contact for various reasons. For example, where a contact has a surface-mount or through-hole contacting portion to be soldered to a corresponding contact on a printed circuit board, the top plate can be omitted from the surface-mount or through-hole contacting portion to improve solderability. In other embodiments of the present invention, other layers, such as the second and third plating layers, can be omitted. 
     In these and other embodiments of the present invention, one or more plating layers can be applied at a varying thickness along a length of the contact. In these embodiments, drum plating can be used. A contact on a carrier can be aligned with a window on an outside drum though which physical vapor deposition or other plating can occur. The window on the outside drum can have an aperture that is varied during rotation by an inside drum, the inside drum inside the outside drum. 
     These contacts can each have a high wear contacting portion to mate with a contact in a corresponding connector. They can have a low-stress beam portion, a high-stress beam portion, and a contacting portion, such as a surface-mount or through-hole contacting portion for mating with a corresponding contact on a printed circuit board or other appropriate substrate. A substrate for the contact can be stamped, for example from a sheet or strip of copper, or a strip that includes strips of copper welded to sides of a strip of a precious-metal alley. An electropolish or chemical polish step can be used to removing stamping burrs, though they can leave nodules or nodes on the contact surface. 
     Accordingly, a first plating layer to provide a surface leveling can be plated on the substrate. This first plating layer can be copper or other material such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, or other material, and it can be plated over the contact substrate to level the surface of the stamped substrate. In these other embodiments of the present invention, the first plating layer can be sufficient and an electropolish step can be omitted. This first plating layer can also provide adhesion between its neighboring substrate and second plating layer. The first plating layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     A second plating layer to provide corrosion resistance can be plated over first plating layer. The second plating layer can act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the second plating layer can be chosen on this basis. This second plating layer can be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material can provide a second plating layer that is more positively charged than a top plate of rhodium-ruthenium, rhodium, or other material. This can cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer can be somewhat harder than a third plating layer above it, which can prevent layers above the third plating layer from cracking when exposed to pressure during a connection. The second plating layer can have a thickness that varies along a length of the contact. For example, it can vary from of 0.1 to 0.2 micrometers, 0.2 to 0.3 micrometers, 0.3 to 0.5 micrometers, 0.3 to 1.5 micrometers, 1.0 to 1.5 micrometers or more than 1.5 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. The second plating layer can be thicker near a high-wear contacting portion, and it can thin away from the high-wear region. 
     A third plating layer to act as an adhesion layer between the second plating layer and a top plate can be plated over the second plating layer. The third plating layer can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer can also provide a leveling effect. The third plating layer can have a thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. 
     A top plate can be formed over the third plating layer. The top plate can be highly corrosive and wear resistant. This top plate can be thinned in the high-stress beam portion to reduce the risk of cracking. The top plate can provide a durable contacting surface for when the contact on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, the top plate can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce its corrosion. The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate can have a thickness less than 0.3 micrometers, between 0.3 and 0.55 micrometers, between 0.3 and 1.0 micrometers, between 0.75 and 1.0 micrometers, more than 1.0 micrometers, or it can have a thickness in a different range of thicknesses. Again, the top plate can be omitted from the surface-mount or through-hole contacting portion. The top plate can be thicker near a high-wear contacting portion, and it can thin away from the high-wear region. 
     In these and other embodiments of the present invention, other layers can be formed on contacts to prevent wear and corrosion. For example, a plastic insulating or nonconductive layer can be formed using electroplastic deposition or electro deposition (ED). This layer can cover portion of a contact to prevent corrosion. A contacting portion of the contact can remain exposed such that it can form an electrical connection with a contact in a corresponding connector. Also, a surface-mount or through-hole contact portion can remain exposed such that it can be soldered to a corresponding contact on a board or other appropriate substrate. 
     These and other embodiments of the present invention can provide a plating stack that is very hard and corrosion resistant, as well as wear resistant. Unfortunately, this hard plating stack can crack or create discontinuities when bent or stressed. This can be particularly problematic along portions of a flexible beam of a contact, which can bend when the contact is mated with a corresponding contact. As such, a contact with this hard plating stack can crack in its beam portion. These cracks can create a short corrosion path to an underlying substrate and other reactive layers in the hard plating stack, thereby accelerating corrosion of the contact. 
     Accordingly, embodiments of the present invention can provide this hard plating stack on a contacting portion of a contact and can reduce or limit the number of layers in the plating stack in a flexible beam area. Where a contact does not include a flexible beam portion, this hard plating stack can be used over a contacting portion and other portions of the contact. 
     In these and other embodiments of the present invention, a substrate formed of copper or copper alloy, niobium and its alloys, tantalum and its alloys, aluminum, aluminum alloy, stainless steel, rhodium, rhodium alloy, ruthenium, ruthenium alloy, rhodium-ruthenium, rhodium-iridium, other platinum group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, silver alloy, other precious metal or its alloys, or other material, can be used for the contact. A leveling layer can be formed over the contact. This leveling layer can be formed of copper or other material and can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a thickness in a different range of thicknesses. A nickel-based support layer, such as a nickel, tin-nickel, nickel-tungsten, nickel phosphate, electroless nickel, nickel based metal, palladium-nickel, nickel-copper or other nickel based layer or other material, can be formed over the leveling layer. This nickel-based support layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. A first gold flash layer can be formed over the nickel-based support layer. This first gold flash can be exposed at a surface-mount or other portion of the contact where the contact is soldered to a board or other substrate. This first gold flash layer can have thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. For example, the first gold flash layer can be twice as thick (or flashed twice) in the beam area of a contact. 
     A first layer of a precious-metal alloy can next be formed on the contact. The first precious-metal alloy can be a rhodium alloy, such as rhodium-ruthenium. This layer can alternatively be formed of rhodium, ruthenium, a ruthenium alloy, rhodium-iridium, other Pt group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, and silver alloy, other precious metal or its alloys. The first precious-metal-alloy layer can be plated over the contacting and beam portions of the contact. The first precious-metal-alloy layer (and subsequent layers described below) can be omitted over a surface-mount or other portion of the contact where the contact is soldered to a board or other substrate. In the contacting portion, the first precious-metal-alloy layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a thickness in a different range of thicknesses. The first precious-metal-alloy layer can have a thickness that tapers to a thinner dimension away from the contacting portion. For example, over the beam, the first precious-metal-alloy layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 2.5 micrometers, 1.5 to 3.0 micrometers, or more than 3.0 micrometers, or it can have a thickness in a different range of thicknesses near the contacting portion, and it can have a thickness of 0.2 to 0.6 micrometers, 0.3 to 0.7 micrometers, 0.7 to 2.0 micrometers, or more than 2.0 micrometers, or it can have a thickness in a different range of thicknesses near the surface mount contacting portion. 
     The first gold flash layer can act as an adhesive for this first precious-metal-alloy layer in order to adhere the first precious metal alloy layer to the nickel-based support layer. A second gold flash layer can be formed over the first precious-metal-alloy layer on the contacting portion to allow adhesion of additional layers used to form the very hard plating stack over the contacting portion. This second gold flash layer and the additional layers may be omitted from a beam portion to reduce the hardness and increase the flexibility of the beam. Also, the first precious-metal-alloy layer and subsequent layers can be omitted from a surface-mount contacting portion of the contact to allow for soldering to a board or other substrate. This second gold flash layer can have thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses. A silver, palladium, or silver-palladium based layer can be formed over the second gold flash layer on the contact portion. This layer can be formed of silver and its alloys, palladium and its alloys, silver-palladium, a ternary silver-palladium-tellurium or quaternary silver-palladium-bismuth-tellurium, palladium-nickel, or other material. This layer can be a more reactive layer than subsequent layers formed on its surface. This more reactive layer can take the brunt of corrosive effects while protecting less reactive layers above and below it. To help ensure that this layer absorbs most of the corrosive effects, it can be formed having a number of micro-cracks or micro-pores in its structure. This silver or silver-palladium based layer can have thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     A second layer of precious-metal alloy can next be formed on the contacting portion. This second precious-metal alloy layer can be formed of the same material as the first layer of precious-metal alloy, or it can be formed of a different material. The second layer of precious-metal alloy can be formed of a rhodium alloy, such as rhodium-ruthenium. This layer can alternatively be formed of rhodium, ruthenium, ruthenium alloy, rhodium-iridium, other Pt group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, and silver alloy, other precious metal or its alloys. The second precious-metal-alloy layer can form a top plate at the surface of the contacting portion. This second precious-metal-alloy layer can form a surface for the very hard plating stack on the contacting portion of the contact. This second precious-metal-alloy layer can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     To avoid cracking of the plating layers at the beam portion of the contact, this very hard plating stack can be limited to the contacting portion of the contact. Since the beam portion of a contact does not directly form electrical connections, it can be protected with a ductile nonconductive protective layer. This layer can be a nonconductive electrophoretic coating formed of a base material containing impurities. The impurities can slow corrosion by increasing a total distance that corrosive elements must travel through the coating before reaching the plating stack under the electrophoretic coating. In these and other embodiments of the present invention, the base material can be acrylic resin, plastic, or other material. The impurities can be one of titanium dioxide, polytetrafluoroethylene, talcum, magnesium oxide, aluminum oxide, calcium oxide, or other inorganic particles. These particles can block corrosion paths through the nonconductive electrophoretic coating, thereby lengthening an effective corrosion path. This nonconductive electrophoretic coating can have a thickness of 2.0 to 5.0 micrometers, 3.0 to 10.0 micrometers, 5.0 to 15.0 micrometers, 10.0 to 20.0 micrometers, or more than 10.0 micrometers, or it can have a thickness in a different range of thicknesses. This electrophoretic coating can be formed in the same or similar manner as the other electrophoretic coatings described herein. As with the other examples disclosed herein, one or more of these layers, such as the second gold flash layer, can be omitted and one or more other layers can be added. 
     While embodiments of the present invention are well-suited to contact structures and their method of manufacturing, these and other embodiments of the present invention can be used to improve the corrosion resistance of other structures. For example, electronic device cases and enclosures, connector housings and shielding, battery terminals, magnetic elements, measurement and medical devices, sensors, fasteners, various portions of wearable computing devices such as clips and bands, bearings, gears, chains, tools, or portions of any of these, can be covered with a precious-metal alloy and plating layers as described herein and otherwise provided for by embodiments of the present invention. The precious-metal alloy and plating layers for these structures can be formed or manufactured as described herein and otherwise provided for by embodiments of the present invention. For example, magnets and other structures for fasteners, connectors, speakers, receiver magnets, receiver magnet assemblies, microphones, and other devices can have their corrosion resistance improved by structures and methods such as those shown herein and in other embodiments of the present invention. 
     In various embodiments of the present invention, the components of contacts and their connector assemblies can be formed in various ways of various materials. For example, contacts and other conductive portions can be formed by stamping, coining, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions can be formed of stainless steel, steel, copper, copper titanium, phosphor bronze, palladium, palladium silver, or other material or combination of materials, as described herein. They can be plated or coated with nickel, gold, palladium, or other material, as described herein. The nonconductive portions, such as the housings and other portions, can be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions can be formed of silicon or silicone, Mylar, Mylar tape, rubber, hard rubber, plastic, nylon, elastomers, liquid-crystal polymers (LCPs), ceramics, or other nonconductive material or combination of materials. 
     Embodiments of the present invention can provide contacts and their connector assemblies that can be located in, or can connect to, various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, wearable computing devices, cell phones, smart phones, media phones, storage devices, keyboards, covers, cases, portable media players, navigation systems, monitors, power supplies, adapters, remote control devices, chargers, and other devices. These contacts and their connector assemblies can provide pathways for signals that are compliant with various standards such as Universal Serial Bus (USB), High-Definition Multimedia Interface® (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt™, Lightning, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. In various embodiments of the present invention, these interconnect paths provided by these connectors can be used to convey power, ground, signals, test points, and other voltage, current, data, or other information. 
     Various embodiments of the present invention can incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention can be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an electronic system according to an embodiment of the present invention; 
         FIG. 2  illustrates a plurality of contacts according to an embodiment of the present invention at a surface of an electronic device; 
         FIG. 3  illustrates a plurality of contacts in a contact assembly housing according to an embodiment of the present invention; 
         FIG. 4  illustrates a cross-section of a contact according to an embodiment of the present invention; 
         FIG. 5  illustrates a plating stack can be used to plate a contacting surface of a contact according to an embodiment of the present invention; 
         FIG. 6  illustrates a method of manufacturing contacts according to an embodiment of the present invention; 
         FIG. 7  illustrates a side view of a stamped or coined contact according to an embodiment of the present invention; 
         FIG. 8  illustrates a connector insert that can be improved by the incorporation of an embodiment of the present invention; 
         FIG. 9  illustrates a side view of a contact according to an embodiment of the present invention; 
         FIG. 10  illustrates a plating stack that can be used to plate a contacting surface of a contact according to embodiments of the present invention; 
         FIG. 11  illustrates a method of manufacturing contacts according to an embodiment of the present invention; 
         FIG. 12  illustrates a method of manufacturing contacts according to an embodiment of the present invention; 
         FIG. 13  illustrates another contact according to an embodiment of the present invention; 
         FIG. 14  illustrates a method of manufacturing contacts according to an embodiment of the present invention; 
         FIG. 15  illustrates a method of forming layers for contacts according to an embodiment of the present invention; 
         FIG. 16  illustrates another method of forming layers for contacts according to an embodiment of the present invention; 
         FIG. 17  illustrates another contact according to an embodiment of the present invention; 
         FIG. 18  illustrates a roll of material that can be stamped to form contacts according to an embodiment of the present invention; 
         FIG. 19  illustrates a pattern that can be employed in stamping contacts according to an embodiment of the present invention; 
         FIG. 20  illustrates another pattern that can be employed in stamping contacts according to an embodiment of the present invention; 
         FIG. 21  illustrates another pattern that can be employed in stamping contacts according to an embodiment of the present invention; 
         FIG. 22  illustrates contact plating layers according to an embodiment of the present invention; 
         FIG. 23  illustrates a dual-drum that can be used in plating a contact according to an embodiment of the present invention; 
         FIG. 24  illustrates an aperture of a plating window of the dual-drum of  FIG. 23 ; 
         FIG. 25  illustrates a contact that can be plated according to an embodiment of the present invention; 
         FIG. 26  illustrates plating layers according to an embodiment of the present invention; 
         FIG. 27  illustrates a number of contacts and a carrier according to an embodiment of the present invention; 
         FIG. 28  illustrates a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention; 
         FIG. 29  illustrates a connector receptacle including a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention; 
         FIG. 30  illustrates a method of manufacturing a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention; 
         FIG. 31  illustrates another contact and its plating stacks according to an embodiment of the present invention; 
         FIG. 32  illustrates a portion of a plating and coating for a contact beam according to an embodiment of the present invention; 
         FIG. 33  illustrates a side view of a connector receptacle according to an embodiment of the present invention; and 
         FIG. 34  illustrates a side view of a top edge of a contacting portion of a contact according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG. 1  illustrates an electronic system according to an embodiment of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims. 
     In this example, host device  110  can be connected to accessory device  120  in order to share data, power, or both. Specifically, contacts  220  on host device  110  can be electrically connected to contacts  222  on accessory device  120 . Contacts  220  on host device  110  can be electrically connected to contacts  222  on accessory device  120  via cable  130 . In other embodiments of the present invention, contacts  220  on host device  110  can be in physical contact and directly and electrically connected to contacts  222  on accessory device  120 . 
     To facilitate a direction connection between contacts  220  on host device  110  and contacts  222  on accessory device  120 , contacts  220  on host device  110  and contacts  222  on accessory device  120  can be located on the surfaces of their respective devices. But this location can make them vulnerable to exposure to liquids or other fluids. This exposure, particularly when there are voltages present on the exposed contacts, can lead to their corrosion. This corrosion can mar the contacts and can be readily apparent to a user. This corrosion can lead to a reduction in operation of the device and can even render the device inoperable. Even when such corrosion does not reach the level of device impairment, it can create a negative impression in the mind of a user that can reflect poorly on the device and the device&#39;s manufacturer. 
     Accordingly, embodiments of the present invention can provide contacts that can be highly corrosion resistant. But ordinarily, such an increase in corrosion resistance can lead to a reduction in manufacturability. Accordingly, embodiments of the present invention can provide contacts that are readily manufactured and can be manufactured using a limited amount of precious resources. Examples are shown in the following figures. 
       FIG. 2  illustrates a plurality of contacts according to an embodiment of the present invention at a surface of an electronic device. In this example, contacts  220  are shown as being at a surface of a device enclosure  210 . Contacts  220  can be insulated from device enclosure  210  by insulating rings of contact assembly housing  230 . In other embodiments of the present invention, for example where device enclosure  210  is nonconductive, the insulation provided by contact assembly housing  230  might not be needed and contact assembly housing  230  can be omitted. In still other embodiments of the present invention, contacts  220  can be used in a connector insert (such as a connector insert shown herein), connector receptacle, or other connector structure. 
     In the following examples, contacts  220  are shown in greater detail. In these and the other embodiments of the present invention, contacts  222  on accessory device  120  can be the same as, substantially similar to, similar to, or different than contacts  220  on host device  110 . 
     In various embodiments of the present invention, a surface of device enclosure  210  can have various shapes or contours. For example, device enclosure  210  can be flat, curved, or have other shapes. Surfaces of contacts  220  can be similarly contoured such that the surfaces of contacts  220  match the adjacent or local contours of device enclosure  210 . In these and other embodiments of the present invention, device enclosure  210  portions can be similarly contoured to match the adjacent or local contours of contacts  220  and device enclosure  210 . While three contacts of similar size are shown in this example, in other embodiments of the present invention, other numbers of contacts, such as two, four, or more than four contacts can be employed and one or more of these contacts can be of a different size. 
       FIG. 3  illustrates a plurality of contacts in a contact assembly housing according to an embodiment of the present invention. In this example, contacts  220  can be located in a contact assembly housing  230 . In various embodiments of the present invention, undersides of contacts  220  can mate with a flexible circuit board, printed circuit board, or other appropriate substrate. 
       FIG. 4  illustrates a cross-section of a contact according to an embodiment of the present invention. As before, contact  220  is shown as being located in insulating rings of contact assembly housing  230 . Contact  220  can include bulk or substrate layer  410 . Contact  220  can have a primarily disk-shape, though contact  220  can have other shapes consistent with embodiments of the present invention. Bulk or substrate layer  410  can include narrow portion  422 , which can be electrically connected by solder region  450  to board  440 . Board  440  can be a flexible circuit board, printed circuit board, or other appropriate substrate. Board  440  can connect to electrical or mechanical, components in the electronic device housing contact  220 . In this way, power and signals can be transferred between this electronic device and a second electronic device via contacts  220 . 
     Contact  220  can include bulk or substrate layer  410 . The resources consumed by contact  220  can be reduced by forming the bulk or substrate layer  410  using a more readily available material, such as copper or a material that is primarily copper based, such as phosphor bronze. In these and other embodiments of the present invention, the bulk or substrate layer  410  can be formed using copper-nickel-tin, copper-nickel-silver alloy, steel, or other appropriate material or alloy. Material having good electrical conductivity and a good availability can be selected for use to form the bulk or substrate layer  410 . The material can also be selected to have a good formability or elongation and hardness similar to that of the material used for the precious-metal-alloy layer  420 . In various embodiments of the present invention, the substrate layer can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. In these and other embodiments of the present invention, the bulk or substrate layer  410  can form the majority of the contact and can have a thickness less than 1 mm, more than 1 mm, between 0.5 mm and 1.5 mm, approximately 1.0 mm, between 1 mm to 10 mm, more than 10 mm, or it can have a thickness in a different range of thicknesses. 
     Bulk or substrate layer  410  can be clad by a precious-metal-alloy layer  420 . Precious-metal-alloy layer  420  can be a high entropy material, such as materials consistent with ASTM Standards B540, B541, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer  420  can be selected to have a good hardness and strength, as well as a high conductivity or low electrical resistance. A material having a good formability or high elongation for improved manufacturability can be selected for use as the precious-metal alloy. In various embodiments of the present invention, the precious-metal-alloy layer  420  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. In these and other embodiments of the present invention, the precious-metal-alloy layer  420  can have a thickness less than 10 micrometers, more than 10 micrometers, from 10 micrometers to 100 micrometers, from 10 micrometers to hundreds of micrometers, more than 100 micrometers, from 100 micrometers to hundreds of micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, one or more intermediate layers can be placed between the precious-metal-alloy layer  420  and the bulk or substrate layer  410 . These intermediate layers can have better corrosion resistance than copper and can be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers can be formed using titanium, steel, tantalum, or other material. This material can be selected based on its availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     Cladding or precious-metal-alloy layer  420  can be plated by one or more plating layers, shown here as plating stack  430 . Plating stacks, such as plating stack  430  can be used to provide a color match, or desired color mismatch, with a device enclosure  210  as shown in  FIG. 1 . Plating stacks, such as plating stack  430  can also be used to provide a hard, scratch resistant surface for contact  220 . An example of such a plating stack is shown in the following figure. 
       FIG. 5  illustrates a plating stack can be used to plate a contacting surface of a contact according to an embodiment of the present invention. This plating stack  430  can include a first plating layer  510  that can be plated over the precious-metal-alloy layer  420  as shown in  FIG. 4  for leveling and adhesion. For example, gold can tend to fill vertical differences across a surface of the precious-metal-alloy layer  420 . These vertical differences can include nodes and nodules that can be left behind by electropolishing and chemical polishing performed on the underlying material. First plating layer  510  can also provide adhesion between the precious-metal-alloy layer  420  and a second plating layer  520 . Instead of gold, first plating layer  510  can be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This first plating layer  510  can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.05 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the first plating layer  510  can be omitted and the second plating layer  520  can be plated directly on the precious-metal layer. 
     In these and other embodiments of the present invention, a second plating layer  520  can be plated over first plating layer  510 . Second plating layer  520  can act as a barrier layer to prevent color leakage from precious-metal-alloy layer  420  to the surface of contact  220 , and the material used for second plating layer  520  can be chosen on this basis. In these and other embodiments of the present invention, second plating layer  520  can be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material can provide a second plating layer  520  that is more positively charged than a top plate  540  of rhodium-ruthenium, rhodium, or other material. This can cause the top plate  540  to act as a sacrificial layer, thereby protecting the underlying palladium in second plating layer  520 . This second plating layer  520  can be somewhat harder than a third plating layer  530  above it, which can prevent layers above the third plating layer  530  from cracking when exposed to pressure during a connection. This second plating layer  520  can have a thickness less than 0.1 micrometers, between 0.1 and 0.5 micrometers, between 0.5 and 1.0 micrometers, between 1.0 and 1.5 micrometers, more than 1.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a third plating layer  530  can be plated over second plating layer  520 . Third plating layer  530  may, like first plating layer  510 , provide leveling and adhesion. For example, gold can tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and can provide adhesion between second plating layer  520  and a top plate  540 . Instead of gold, third plating layer  530  can be formed of nickel, palladium, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer  530  can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.05 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, top plate  540  can be plated over third plating layer  530 . Top plate  540  can provide a durable contacting surface for when contact  220  on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, top plate  540  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  540  can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce the corrosion of top plate  540 . The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. Top plate  540  can have a thickness less than 0.5 micrometers, between 0.5 and 0.75 micrometers, between 0.75 and 0.85 micrometers, between 0.85 and 1.1 micrometers, more than 1.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, third plating layer  530  can be omitted and top plate  540  can be plated directly on second plating layer  520 . 
     In these and other embodiments of the present invention, top plate  540  can be plated directly over first plating layer  510  and second plating layer  520  and third plating layer  530  can be omitted. 
     In these and other embodiments of the present invention, the plating materials used can be selected based on availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. These and the other contacts shown herein and consistent with embodiments of the present invention can be formed in various ways. An example is shown in the following figure. 
       FIG. 6  illustrates a method of manufacturing contacts according to an embodiment of the present invention. This and similar methods can be used to manufacture the above and other contacts shown herein, as well as other contacts according to embodiments of the present invention. In this example, a bulk or substrate layer  410  can be at least partially covered by a layer of precious-metal-alloy layer  420 . These layers can be provided in rolls  610 . Rolls  610  can be stamped or coined to form contacts  220 . Carriers  620 , attached to contacts  220 , can similarly be stamped. Carriers  620  can be used to manipulate contacts  220  during later processing steps such as blasting, polishing, etching, annealing, or other processing steps. Contacts  220  can be stamped in a manner to efficiently utilize the precious-metal-alloy layer  420 . Unused material from precious-metal layers, such as precious-metal-alloy layer  420 , and bulk or substrates, such as bulk or substrate layer  410 , can be recycled or otherwise reused. 
     It can be very difficult to plate bulk or substrate layer  410  with a precious-metal-alloy layer  420 . Accordingly, in this embodiment of the present invention, contacts  220  can be stamped from bulk or substrate layer  410  and precious-metal-alloy layer  420 . This stamping process can be coining or other type of process. This stamping process can bond the precious-metal-alloy layer  420  to the bulk or substrate layer  410 . This stamping process can be done at an elevated temperature (which can be used for annealing.) The material of roll  610  can be stretched or elongated during stamping or coining in order to bond the precious-metal-alloy layer  420  and bulk or substrate layer  410 . For example, a 35, 50, or 70 percent elongation can be used. 
     In these and other embodiments of the present invention this diffusion or bonding layer can be formed when the precious-metal alloy is bonded or clad to the substrate. This bonding layer can be an intermetallic bond of the precious-metal-alloy layer  420  and the alloy of the bulk or substrate layer  410 . This diffusion or bonding layer can be less than 1 micrometer, more than 1 micrometer, 1 to 5 micrometers, 5 micrometers, or more than 5 micrometers thick. 
     This and similar processes can be used to form contacts described herein and in other embodiments of the present invention. An example of a stamped contact is shown in the following figure. 
       FIG. 7  illustrates a side view of a stamped or coined contact according to an embodiment of the present invention. Contact  220  can include a bulk or substrate layer  410  having a narrow portion  422 . Narrow portion  422  can be soldered to a flexible circuit board, printed circuit board, or other appropriate substrate. Bulk or substrate layer  410  can be clad with a precious-metal-alloy layer  420 . Tail portion  710  can remain after carrier  620  has been broken away or otherwise physically disconnected from contact  220 . After stamping, contact  220  can be blasted, annealed, polished, plated, or subjected to other processing steps, as shown herein. 
     In the above examples, contacts  220  are shown as contacts at a surface of a device enclosure  210 . In other embodiments of the present invention, the same or similar structures, layers, manufacturing, and processing steps can be used to form contacts for a connector insert or a connector receptacle, for example a connector receptacle where contacts are located in an opening in a device enclosure. Examples of such contacts that can be used in a connector insert or connector receptacle are shown in the following figures. These and other embodiments of the present invention can be used as contacts on a surface of a device or elsewhere as shown above as well. 
       FIG. 8  illustrates a connector insert that can be improved by the incorporation of an embodiment of the present invention. In this example, a connector insert can include a ground ring  810  surrounding an opening  830  for contacts  820 . Contacts  820  can have a length along a major axis in the Y direction that is longer than a length along a minor axis in the X direction. Typically, opening  830  can be filled with an overmold such that only surfaces of contacts  820  are exposed. While contacts  820  are shown here as being located in a connector insert, in other embodiments of the present invention, contacts  820 , and the other contacts shown herein and those consistent with embodiments of the present invention can be located at a surface of a device enclosure, in a connector receptacle, or in another type of contacting structure. 
       FIG. 9  illustrates a side view of a contact according to an embodiment of the present invention. Contact  820  can include a bulk or substrate layer  910 . Bulk or substrate layer  910  can terminate in a narrow portion  912 . Narrow portion  912  can be electrically connected through solder  960  to a contact on board  970 , which can be a flexible circuit board, printed circuit board, or other appropriate substrate. Areas  950  below portions of bulk or substrate layer  910  can include air gaps to reduce side-to-side capacitance between contacts  820 . Board  970  can connect to conductors or electrical or mechanical, components in the connector insert housing contact  820 . In this way, power and signals can be transferred between a first electronic device and a second electronic device via contacts  820 . 
     Bulk or substrate layer  910  can be clad by precious-metal-alloy layer  920 . Precious-metal-alloy layer  920  can be plated by plating stack  930 . Plating stack  930  can extend along sides of the contact shown as regions  933 . Regions  933  can be omitted or can extend along other portions of the underside of contact  820 . Contact  820  can be located in an overmold region  940  in opening  830  in ground ring  810  as shown in  FIG. 8 . 
     The resources consumed by contact  820  can be reduced by forming the bulk or substrate layer  910  using a readily available material, such as copper or a material that is primarily copper based, such as phosphor bronze. In these and other embodiments of the present invention, the bulk or substrate layer  910  can be formed using copper-nickel-tin, copper-nickel-silver alloy, steel, or other appropriate material or alloy. Material having good electrical conductivity and a good availability can be selected for use to form bulk or substrate layer  910 . The material can also be selected to have a good formability and elongation and hardness similar to that of the material used for the precious-metal-alloy layer  920 . In various embodiments of the present invention, the bulk or substrate layer  910  can have a Vickers hardness of below 100, between 100-200, between 200-300, over 300, or a hardness in another range. In these and other embodiments of the present invention, the bulk or substrate layer  910  can form the majority of the contact and can have a thickness less than 1 mm, more than 1 mm, from 0.5 to 1.5 mm, approximately 1.0 mm, between 1 mm and 10 mm, more than 10 mm, or it can have a thickness in a different range of thicknesses. 
     Bulk or substrate layer  910  can be clad by a precious-metal-alloy layer  920 . Precious-metal-alloy layer  920  can be a high entropy material, such as materials consistent with ASTM Standards B540, B541, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer  920  can be selected to have a good hardness and strength, as well as a high conductivity or low electrical resistance. A material having a good formability and high elongation for improved manufacturability can be selected for use as the precious-metal alloy. In various embodiments of the present invention, the precious-metal-alloy layer  920  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. In these and other embodiments of the present invention, the precious-metal-alloy layer  920  can have a thickness less than 10 micrometers, more than 10 micrometers, from 10 micrometers to 100 micrometers, from 10 micrometers to hundreds of micrometers, more than 100 micrometers, from 100 micrometers to hundreds of micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, one or more intermediate layers can be placed between precious-metal-alloy layer  920  and the bulk or substrate layer  910 . These intermediate layers can have better corrosion resistance than copper and can also be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers can be formed using titanium, steel, tantalum, or other material. This material can be selected based on its availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     Cladding or precious-metal-alloy layer  920  can be plated by one or more plating layers, shown here as plating stack  930 . Plating stack  930  can be used to provide a color match, or desired color mismatch, with ground ring  810  as shown in  FIG. 8 . Plating stack  930  can also be used to provide a hard, scratch resistant surface for contact  820 . An example of such a plating stack is shown in the following figure. 
       FIG. 10  illustrates a plating stack that can be used to plate a contacting surface of a contact according to embodiments of the present invention. This plating stack  930  can include a first plating layer  1010  that can be plated over the precious-metal-alloy layer  920  as shown in  FIG. 9  for leveling and adhesion. For example, gold can tend to fill vertical differences across a surface of the precious-metal-alloy layer  920 . These vertical differences can include nodes and nodules that can be left behind by electropolishing and chemical polishing performed on the underlying material. First plating layer  1010  can also provide adhesion between the precious-metal-alloy layer  920  and a second plating layer  1020 . Instead of gold, the first plating layer  1010  can be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This first plating layer  1010  can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.05 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a second plating layer  1020  can be plated over first plating layer  1010 . Second plating layer  1020  can act as a barrier layer to prevent color leakage from the precious-metal-alloy layer  920  to the surface of the contact, and the material used can be chosen on that basis. In these and other embodiments of the present invention, the second plating layer  1020  can be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material can provide a second plating layer  1020  that is more positively charged than a top plate  1040  of rhodium-ruthenium, rhodium, or other material. This can cause the top plate  1040  to act as a sacrificial layer, thereby protecting the underlying palladium in second plating layer  1020 . This second plating layer  1020  can be somewhat harder than a third plating layer  1030  above it, which can prevent layers above the third plating layer  1030  from cracking when exposed to pressure during a connection. This second plating layer  1020  can have a thickness less than 0.1 micrometers, between 0.1 and 0.5 micrometers, between 0.5 and 1.0 micrometers, between 1.0 and 1.5 micrometers, more than 1.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, first plating layer  1010  can be omitted and second plating layer  1020  can be plated directly on precious-metal-alloy layer  920 . 
     In these and other embodiments of the present invention, a third plating layer  1030  can be plated over second plating layer  1020 . Third plating layer  1030  may, like first plating layer  1010 , can provide leveling and adhesion. For example, gold can tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and can provide adhesion between second plating layer  1020  and a top plate  1040 . Instead of gold, third plating layer  1030  can be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer  1030  can have a thickness less than 0.01 micrometers, between 0.01 and 0.05 micrometers, between 0.05 and 0.1 micrometers, between 0.05 and 0.15 micrometers, more than 0.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, top plate  1040  can be plated over third plating layer  1030 . Top plate  1040  can provide a durable contacting surface for when contact  820  on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. Top plate  1040  can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce the corrosion of top plate  540 . The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. In various embodiments of the present invention, top plate  1040  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  1040  can have a thickness less than 0.5 micrometers, between 0.5 and 0.75 micrometers, between 0.75 and 0.85 micrometers, between 0.85 and 1.1 micrometers, more than 1.1 micrometers, or it can have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, third plating layer  1030  can be omitted and top plate  1040  can be plated directly on second plating layer  1020 . 
     In these and other embodiments of the present invention, top plate  1040  can be plated directly over first plating layer  1010  and either or both plating layers  1020  and  1030  can be omitted. 
     In these and other embodiments of the present invention, the plating materials used can be selected based on availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     These and the other contacts shown herein and consistent with embodiments of the present invention can be formed in various ways. An example is shown in the following figure. 
       FIG. 11  illustrates a method of manufacturing contacts according to an embodiment of the present invention. This and similar methods can be used to manufacture the above and other contacts shown herein, as well as other contacts according to embodiments of the present invention. 
     In this example, bulk or substrate layer  910  can be at least partially covered by a precious-metal-alloy layer  920 . These layers can be provided on a roll, as shown as roll  610  in  FIG. 6 . Contacts  820  can be stamped, coined, or otherwise formed in these layers. Carriers (not shown) can be stamped at the same time and used to handle contacts  820  during further processing steps. 
     In other embodiments of the present invention, precious-metal-alloy layer  920  can be embedded in bulk or substrate layer  910 . An example is shown in the following figure. 
       FIG. 12  illustrates a method of manufacturing contacts according to an embodiment of the present invention. In this example, a groove has been skived, cut, etched, or otherwise formed in a surface of bulk or substrate layer  910 . A precious-metal-alloy layer  920  has been placed or formed in this groove. As before, contacts  820  can be stamped or coined. Carriers (not shown) can be stamped at the same time and used to handle contacts  820  during further processing steps. 
       FIG. 13  illustrates another contact according to an embodiment of the present invention. In this example, some or all of the layers and structures can be identical to the contact shown in  FIG. 9 . Precious-metal-alloy layer  920  can extend along sides of bulk or substrate layer  910 . This can further help to reduce corrosion. Specifically, if moisture or liquid seeps between  940  and contact  820 , sides of bulk or substrate layer  910  can be exposed to corrosion. 
     This corrosion can be reduced by the presence of side portions  922  of precious-metal-alloy layer  920 . Side portions  922  can be formed at tips or ends of contacts  820 , for example, at ends of the major axis of contacts  820 . In other examples, the side portions  922  of precious-metal-alloy layer  920  can be around all or portions of sides of bulk or substrate layer  910 . 
     Side portions  922  of precious-metal-alloy layer  920  can be formed in various ways. Examples are shown in the following figures. 
       FIG. 14  illustrates a method of manufacturing contacts according to an embodiment of the present invention. In this example, one or more grooves have been formed in bulk or substrate layer  910 . That is, one or more grooves have been skived, cut, etched, or otherwise formed in a surface of bulk or substrate layer  910 . These one or more grooves have been filled in with precious-metal-alloy layer  920 . Two grooves have a greater depth can be used to form side portions  922 . Contacts  820  and carriers can be stamped or coined as described herein. 
     The one or more grooves in bulk or substrate layer  910  can be formed in various ways. Examples are shown in the following figures. 
       FIG. 15  illustrates a method of forming layers for contacts according to an embodiment of the present invention. In this example, groove  1520  can be formed in bulk or substrate layer  910 . This groove can be formed by skiving, cutting, etching, or other appropriate method. Deeper grooves  1510  can then be formed in bulk or substrate layer  910  by skiving, cutting, etching, or other process step. The resulting grooves can be filled with precious-metal-alloy layer  920 . 
       FIG. 16  illustrates another method of forming layers for contacts according to an embodiment of the present invention. In this example, grooves  1610  can be initially formed by skiving, cutting, etching, or other process in bulk or substrate layer  910 . Groove  1620  can then be formed, again by skiving, cutting, edging, or other process step. Cladding or precious-metal-alloy layer  920  can then be used to fill the opening formed by grooves  1610  and  1620 . 
       FIG. 17  illustrates another contact according to an embodiment of the present invention. In this example, some or all of the layers and structures can be identical or similar to the contact shown in  FIG. 9 . In this example, either or both bulk or substrate layer  910  and precious-metal-alloy layer  920  can include tabs and notches  1710  and  1720 . These tabs and notches  1710  and  1720  can be used to secure bulk or substrate layer  910  to precious-metal-alloy layer  920 , for example in conjunction with laser welding. In various embodiments of the present invention, either of these tabs can be long enough to pass through the adjacent layer and be riveted or laser welded on the other side to secure bulk or substrate layer  910  to precious-metal-alloy layer  920 . 
     In these and other embodiments of the present invention, contacts can be formed in other ways and have different plating layers. For example, strips of a copper alloy or other material can be butt-welded or otherwise fixed or attached to sides of a strip of a precious-metal alloy to form a strip or roll of material for stamping. Contacts can be stamped such that all of the contact is formed of the precious-metal alloy while a carrier is formed of the copper alloy or other material. Contacts can also be stamped such that only portions, such as a contacting portion, are formed of the precious-metal alloy while the remainder of the contact and a carrier is formed of the copper alloy or other material in order to conserve resources. Examples are shown in the following figures. 
       FIG. 18  illustrates a roll of material that can be stamped to form contacts according to an embodiment of the present invention. A strip of precious-metal alloy  1820  can be butt-welded or otherwise fixed or attached to edges  1850  of copper alloy strips  1830  and  1840 . These strips can be rolled into roll  1810  for handling and manufacturing purposes. In various embodiments of the present invention, contacts can be stamped such that all, or portions of, contacts are formed of precious-metal alloy  1820 . In these and other embodiments of the present invention, carriers, which can be used to handle the contacts during manufacturing, can be formed in the copper alloy strips  1830  and  1840 . In various embodiments of the present invention, the comparative width of these strips can vary. Also, the materials used can vary. For example, precious-metal alloy  1820  can be replaced with another material. Copper alloy strips  1830  and  1840  can instead be formed of copper, steel, or other material. Examples showing how contacts can be stamped to be fully or partially formed of precious-metal alloy  1820  are shown in the following figures. 
       FIG. 19  illustrates a pattern that can be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  can be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . In this example, contacts  1910  can be stamped such that they are fully formed of precious-metal alloy  1820 . Carriers (not shown), can be formed in the copper alloy strips  1830  and  1840 . With the contacts  1910  in this longitudinal direction, the usage of the precious-metal alloy  1820  is good. Also, the grain direction is such that the durability of the resulting contacts can be good. In this embodiment the present invention, a feed direction into a stamping machine can be indicated by arrow  1920 . 
       FIG. 20  illustrates another pattern that can be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  can be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . Contacts  1910  can be stamped such that they are fully formed of precious-metal alloy  1820 . Carriers (not shown) can be formed in copper alloy strips  1830  and  1840 . With contacts  1910  in this transverse direction, material utilization can be improved over the example of  FIG. 19 , though the grain direction might not be as optimal. As before, a feed direction into a stamping machine can be indicated by arrow  1920 . 
       FIG. 21  illustrates another pattern that can be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  can be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . In this example, a contacting portion  2110  of contacts  1910  can be formed of precious-metal alloy  1820 , while a remainder  2120  of contacts  1910  can be formed in the copper alloy strips  1830  and  1840 . As before, a feed direction into a stamping machine can be indicated by arrow  1920 . 
     In these and other embodiments of the present invention, precious-metal-alloy layers or contact portions, such as precious-metal alloy  1820 , can be a high entropy material, such as materials consistent with ASTM Standards B540, B541, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal alloy  1820  can be selected to have a good hardness and strength, as well as a high conductivity or low electrical resistance. A material having a good formability or high elongation for improved manufacturability can be selected for use as the precious-metal alloy  1820 . In various embodiments of the present invention, the precious-metal alloy  1820  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. 
     These and other embodiments of the present invention can include various plating layers at a contacting or other portion of a contact. Examples are shown in the following figure. 
       FIG. 22  illustrates plating layers according to an embodiment of the present invention. In this example, contacts such as the contacts shown in the various examples herein can be plated with plating stack  2210 . Also, other types of contacts, for example contacts formed by stamping or other process, and formed of copper, copper alloy, or other material, can be plated with this plating stack  2210 . After stamping or other manufacturing step, an electropolish step can be used to removing stamping burrs from the substrate, which could otherwise expose nickel silicides or other particles in the substrate. Unfortunately, the electropolish step can leave nodules on the contact surface. Chemical polish can be used in its place, though a chemical polish can leave nodes behind on the contact surface. 
     Accordingly, a first plating layer  2220  can be plated on the substrate to provide a surface leveling. This first plating layer  2220  can be copper or other material, such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, and it can be plated over the contact substrate to level the surface of the substrate and cover nodules left by electropolishing, or nodes left by chemical polishing, as well as remaining burrs or other defects from the stamping process. In these other embodiments of the present invention, the first plating layer  2220  can be sufficient and an electropolish step can be omitted. The first plating layer  2220  can also provide adhesion between the substrate and a second plating layer  2230  that can be plated over the first plating layer  2220 . The first plating layer  2220  can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 4.5 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. In other embodiments of the present invention, this first plating layer  2220  can be omitted. 
     Cracks in these plating layers can provide pathways for fluids that can cause corrosion. Accordingly, a second, harder plating layer  2230  to prevent layers above it from cracking can be plated over the first plating layer  2220 . This second plating layer  2230  can be formed of an electroless nickel composite. This second plating layer can be formed of a nickel-tungsten alloy. This second plating layer  2230  can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 2.0 micrometers, 2.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. In other embodiments of the present invention, this second plating layer  2230  can be omitted. 
     A third plating layer  2240  can work in conjunction with the second plating layer  2230 . The third plating layer  2240  can be plated over the second plating layer. This third plating layer  2240  can be soft to absorb shock and thereby minimize cracking in the layers above the third plating layer  2240 . The third plating layer  2240  can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer  2240  can provide adhesion between its neighboring layers and can provide a leveling effect as well. This third plating layer  2240  can have a thickness of 0.55 to 0.9 micrometers, 0.5 to 1.25 micrometers, 1.25 to 2.5 micrometers, 2.5 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. In various embodiments of the present invention, these second plating layer  2230  and third plating layer  2240  can be omitted, or the second plating layer  2230  can be omitted, though other layers can be added or omitted as well or instead. 
     A fourth plating layer  2250  to provide corrosion resistance can be plated over third plating layer  2240 . The fourth plating layer  2250  layer can act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the fourth plating layer  2250  can be chosen on this basis. This layer can be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material can provide a fourth plating layer  2250  that is more positively charged than a top plate  2270  of rhodium-ruthenium, rhodium, or other material. This can cause the top plate  2270  to act as a sacrificial layer, thereby protecting the underlying palladium in fourth plating layer  2250 . This fourth plating layer  2250  can be somewhat harder than a fifth plating layer  2260  above it, which can prevent layers above the fourth plating layer  2250  from cracking when exposed to pressure during a connection. The fourth plating layer  2250  can have a thickness of 0.5 to 0.8 micrometers, 0.5 to 1.0 micrometers, 1.0 to 1.5 micrometers, 1.5 to 3.0 micrometers, or more than 3.0 micrometers, or it can have a thickness in a different range of thicknesses. When palladium is used, it can be plated at a rate of 0.6 plus or minus 0.1 ASD or other appropriate rate. 
     A fifth plating layer  2260  to act as an adhesion layer between the fourth plating layer  2250  and a top plate  2270  can be plated over the fourth plating layer  2250 . The fifth plating layer  2260  can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The fifth plating layer  2260  layer can also provide further leveling. The fifth plating layer  2260  layer can have a thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.10 to 0.20 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses. 
     A top plate  2270  can be formed over the fifth plating layer  2260 . The top plate  2270  can be highly corrosive and wear resistant. This top plate  2270  can be thinned in high-stress locations to reduce the risk of cracking. Top plate  2270  can provide a durable contacting surface for when the contact on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, top plate  2270  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  2270  can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce its corrosion. The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate  2270  can have a thickness less than 0.5 micrometers, between 0.5 and 0.75 micrometers, between 0.65 and 1.0 micrometers, 0.75 and 1.0 micrometers, between 1.0 and 1.3 micrometers, more than 1.3 micrometers, or it can have a thickness in a different range of thicknesses. 
     In various embodiments of the present invention, these layers can be varied. For example, top plate  2270  can be omitted over portions of the contact for various reasons. For example, where a contact has a surface-mount or through-hole contacting portion to be soldered to a corresponding contact on a printed circuit board, top plate  2270  can be omitted from the surface-mount or through-hole contacting portion. In other embodiments of the present invention, other layers, such as the second plating layer  2230  and third plating layer  2240 , can be omitted. 
     Also, in these and other embodiments of the present invention, one or more plating layers can be applied at a varying thickness along a length of the contact. In these embodiments, drum plating can be used. A contact on a carrier can be aligned with a window on a first drum though which physical vapor deposition or other plating step can occur. The window on the first drum can have an aperture that is varied during rotation by a window on a second drum, the second drum inside the first drum. An example is shown in the following figure. 
       FIG. 23  illustrates a dual-drum that can be used in plating a contact according to an embodiment of the present invention. In this example, an outside drum  2310  can have a number of windows  2320  around an outside edge. Contacts on a carrier (as shown in  FIG. 27 ) can be aligned to each window  2320 . The outside drum  2310  can rotate and a plating layer can be formed on the contacts. The aperture of each window  2320  can vary during rotation and can be modulated by windows  2330  on a second inside drum (not shown), where the inside drum turns at a higher rate than the outside drum  2310 . The variation in aperture during rotation can cause portions of the contacts that are exposed for longer durations to receive more plating. An example of this variation in aperture is shown in the following figure. 
       FIG. 24  illustrates an aperture of a plating window of the dual-drum of  FIG. 23 . A contact on a carrier (as shown in  FIG. 27 ) can be aligned with each window  2320  on outside drum  2310 . When a window  2330  on the inside drum is aligned with a window  2320  on the outside drum, the aperture is fully opened and an entire contact (or entire portion of a contact) can be plated. As the inside drum rotates relative to the outside drum  2310 , an obstructing portion  2410  between windows  2330  on the inside drum can progressively block window  2320 . This narrowing aperture can be indicated as  2321  and  2322  in this figure. An example of a contact that can be plated using this dual-drum apparatus is shown in the following figure. 
       FIG. 25  illustrates a contact that can be plated according to an embodiment of the present invention. Contact  1910  can have a high-wear contacting portion  2510  to mate with a contact in a corresponding connector. Contact  1910  can have a low-stress beam portion  2520 , a high-stress beam portion  2530 , and a contacting portion  2540 , such as a surface-mount or through-hole contacting portion for mating with a corresponding contact on a printed circuit board or other appropriate substrate (not shown). Accordingly, contact  1910  can have a hard layer that is thicker at the high-wear contacting portion  2510  to prevent wear, and thinner at the high-stress beam portion  2530  to avoid cracking, which again can act as a pathway for moisture seepage and thus corrosion. 
     Contacts, such as contacts  1910 , can be located in a connector receptacle, a connector insert, or elsewhere in a connector system. 
     A substrate for contact  1910  can be stamped, for example from a sheet or strip of copper, or a strip that includes strips of copper welded to sides of a strip of a precious-metal alley, or as shown in any of the examples shown herein. An electropolish or chemical polish step can be used to removing stamping burrs, though they can leave nodules or nodes on the contact surface. Again, this contact  1910  can be plated in various embodiments of the present invention. An example is shown in the following figure. 
       FIG. 26  illustrates plating layers according to an embodiment of the present invention. In this example, a plating stack  2610  can include four layers, though in various embodiments of the present invention, there can be less than four or more than four layers. A first plating layer  2620  to provide a surface leveling can be plated on the substrate. This first plating layer  2620  can be copper or other material such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, or other material, and first plating layer  2620  can be plated over the contact substrate to level the surface of the stamped substrate. In these other embodiments of the present invention, first plating layer  2620  can be sufficient and an electropolish step can be omitted. This first plating layer  2620  can also provide adhesion between its neighboring substrate and second plating layer  2630 . First plating layer  2620  can have a thickness of 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a thickness in a different range of thicknesses. 
     A second plating layer  2630  to provide corrosion resistance can be plated over first plating layer  2620 . The second plating layer  2630  can act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the second plating layer  2630  can be chosen on this basis. This second plating layer  2630  can be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material can provide a second plating layer  2630  that is more positively charged than a top plate  2650  of rhodium-ruthenium, rhodium, or other material. This can cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer can be somewhat harder than a third plating layer  2640  above it, which can prevent layers above the second plating layer  2630  from cracking when exposed to pressure during a connection. The second plating layer  2630  can have a thickness that varies along a length of the contact. For example, it can vary from of 0.1 to 0.2 micrometers, 0.2 to 0.3 micrometers, 0.3 to 0.5 micrometers, 0.3 to 1.5 micrometers, 1.0 to 1.5 micrometers or more than 1.5 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. The second plating layer  2630  can be thicker near a high-wear contacting portion, and it can thin away from the high-wear region. This can provide a thicker hard layer over contacting portion  2510  for wear resistance and a thinner hard layer over high-stress beam portion  2530  of contact  1910  (as shown in  FIG. 25 ) to avoid cracking. 
     A third plating layer  2640  to act as an adhesion layer between the second plating layer  2630  and a top plate  2650  can be plated over the second plating layer  2630 . The third plating layer  2640  can be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer can also provide a leveling effect. The third plating layer  2640  can have a thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. 
     A top plate  2650  can be formed over the third plating layer. The top plate  2650  can be highly corrosive and wear resistant. This top plate  2650  can be thinned in the high-stress beam portion  2530  of contact  1910  (as shown in  FIG. 25 ) to reduce the risk of cracking. The top plate  2650  can be thicker to provide a durable contacting surface for contacting portion  2510  of contact  1910  (as shown in  FIG. 25 ) for when the contact on the electronic device housing the contact is mated with a corresponding contact on a second electronic device. In various embodiments of the present invention, the top plate  2650  can have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate  2650  can be formed using rhodium-ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium-ruthenium or rhodium can help oxygen formation, which can reduce its corrosion. The percentage of rhodium can be between 85 to 100 percent by weight, for example, it can be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material can be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. Top plate  2650  can have a thickness less than 0.3 micrometers, between 0.3 and 0.55 micrometers, between 0.3 and 1.0 micrometers, between 0.75 and 1.0 micrometers, more than 1.0 micrometers, or it can have a thickness in a different range of thicknesses. Again, top plate  2650  can be omitted from the surface-mount or through-hole contacting portion of contact  1910  (as shown in  FIG. 25 ). 
       FIG. 27  illustrates a number of contacts and a carrier according to an embodiment of the present invention. In this example, a number of contacts  1910  can be attached to a carrier  2710 . A roll direction can be indicated by arrow  2720 . 
     In these and other embodiments of the present invention, other layers can be formed on contacts to prevent wear and corrosion. An example is shown in the following figure. 
       FIG. 28  illustrates a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention. In this example, a plastic insulating layer or coating  2850  can be formed using electrophoretic deposition (ED) or other appropriate method. This layer or coating  2850  can cover portion of a contact  1910 , primarily beam  2810 , to prevent corrosion. A contacting portion  2820  of contact  1910  can remain exposed such that it can form an electrical connection with a contact in a corresponding connector. Also, a surface-mount contacting portion  2830  or through-hole contact portion (not shown) can remain exposed such that it can be soldered to a corresponding contact on a board or other appropriate substrate. 
       FIG. 29  illustrates a connector receptacle including a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention. This connector can include a number of contacts  1910  supported by a housing  2970 . Housing  2970  can include a front opening  2972  for accepting a connector insert (not shown) and can be at least partially surrounded by top shield  2980  and bottom shield  2982 . Side ground contact  2960  can contact a shield of the connector insert when the connector insert is inserted into the connector receptacle. 
     Each contact  1910  can include beam  2910 , contacting portion or contact area  2920 , surface-mount contact portion  2830 , and mechanical stabilizing portion  2940 . Contacting portion or contact area  2920  can mate with a contact in a corresponding connector insert when the connector insert is inserted into the connector receptacle. Surface-mount contact portion  2830  can be soldered to a flexible or printed circuit board or other appropriate substrate to form an electrical connection to traces and planes in the board. Mechanical stabilizing portion  2940  can be molded or inserted into housing  2970  to fix contact  1910  in place in the connector receptacle. 
     Beam  2910  can deflect when a connector insert is inserted into the connector receptacle. This deflection can make the beam more susceptible to cracking due to corrosion. This effect can be referred to as stress corrosion cracking. Similarly, the effects of corrosion can be more severe at the beam due to this defection. That is, there can be either more corrosion, or more sensitivity to corrosion, at base of beam  2910  near mechanical stabilizing portion  2940 , such that small amounts of corrosion can destroy or damage contact  1910 . In some contacts, plating on base of beam  2910  can crack and fatigue, and this can cause corrosion to accelerate. 
     Accordingly, these and other embodiments of the present invention can use electrophoretic deposition (ED) or other appropriate method to form ED coating  2950  to protect beam  2910  from corrosion. This electrophoretic deposition can form a nonconductive coating, though in these and other embodiments of the present invention, the coating can be conductive or partially conductive. In these and other embodiments of the present invention, the electrophoretic deposition process used can be an electrocoating, cathodic or anodic electrodeposition, electroplastic deposition, electro deposition, electrophoretic coating, electrophoretic painting, or other appropriate process. 
     Contact  1910  can be formed in various ways. For example, contact  1910  can have either or both contacting area  2920  and surface mount contact portion  2930  covered by a masking layer. The masking layer can be wax, paraffin, or other material. This material can be applied mechanically, by printing, such as with an ink jet, roller, pad, or other applicator, or by other method. 
     Contact  1910  can then be coated with ED coating  2950 . In these and other embodiments of the present invention, the coating material can be an acrylic resin, plastic, or other material. The acrylic resin, or other material, can be mixed with either or both ether and alcohol or other volatile solvents. For example, the coating material can be an acrylic resin mixed with volatile solvents, such as alcohol, butanol, ethaline, glycol, mono-butyl, and others. The ether and alcohol can allow the resin to be in liquid form before application. Contact  1910  can be placed in this bath at a high voltage, for example 20-100 volts. The voltage can attract resin ions to contact  1910  and the resin can form ED coating  2950  on contact  1910 . 
     After ED coating  2950  has been applied, the masking layer can be removed. For example, where the masking layer is wax, it can be removed using hot water. This can also help to set the ED coating  2950  on contact  1910 . 
     As shown in  FIG. 21  above, in some embodiments of the present invention, a tip of contact  1910  can be formed of a precious-metal alloy. In this example, the contact area  2920  (and  2820  in  FIG. 28 ) can be formed of precious-metal alloy while other materials can be used to form beam  2910 , since beam is coated with ED coating  2950 . The use of resin or other ED coating  2950  can allow the use of a mix of materials. For example, a hard, precious-metal alloy or other material can be used for contact areas  2920  without the consequence of having a brittle beam  2910 . This can allow the beam  2910  to be formed of a more flexible, less brittle material. Moreover, the gradient coating techniques shown in  FIG. 25  above can be employed as well. 
     Where contacting area  2920  is formed of a precious-metal alloy, it can be desirable to save resources by reducing its size. This can require a more accurate application of the masking layer. Accordingly, in these and other embodiments of the present invention the masking layer can be formed by printing, such as with an ink jet, roller, pad, or other applicator. These and other embodiments of the present invention can provide contacts that are formed using 3-D printing. The precious-metal alloys used can be the same or similar to those in the examples herein and consistent with other embodiments of the present invention. 
     Contacts, such as contacts  1910  and the other contacts in these examples, can be formed of various materials. For example, the beams and other contact portions can be formed of copper or other materials. The beams and other portions can be plated with various layers, such as those shown in  FIGS. 4, 9, 22, and 26 . 
     Contacts, such as contacts  1910 , can be formed in various ways in these and other embodiments of the present invention. An example is shown in the following figure. 
       FIG. 30  illustrates a method of manufacturing a contact partially plated with plastic, resin, or other material according to an embodiment of the present invention. In act  3010 , a contact, such as contact  1910 , and a carrier can be formed. The contact and its carrier can be formed by stamping, forging, molding, metal-injection molding, 3-D printing, or other manufacturing process, for example the process shown in  FIG. 21  or any of the other processes shown herein or otherwise consistent with embodiments of the present invention. The contacts can be plated, for example using layers as shown in  FIGS. 4, 9, 22, and 26 . A masking layer can be applied to a contact area, such as contact area  2920 , in act  3020 . Other regions, such as surface mount contact portion  2930 , can be masked as well. This masking layer can be applied mechanically, by printing, such as with an ink jet, roller, pad, or other applicator, or by other method. The masking layer can be formed of wax, paraffin, or other material. 
     In act  3030 , an electrophoretic coating, such as ED coating  2950 , can be applied to the contact using electrophoretic deposition or other appropriate method. In these and other embodiments of the present invention, the electrophoretic deposition process used can be an electrocoating, cathodic or anodic electrodeposition, electroplastic deposition, electro deposition, electrophoretic coating, electrophoretic painting, or other appropriate process. In these and other embodiments of the present invention, the coating material can be an acrylic resin, plastic, or other material. The coating material can be nonconductive. The acrylic resin, or other material, can be mixed with either or both ether and alcohol. For example, the coating material can be an acrylic resin mixed with volatile solvents, such as alcohol, butanol, ethaline, glycol, mono-butyl, and others. The ether and alcohol can allow the coating material to be in liquid form. The contact, such as contact  1910 , can be placed in this bath at a high voltage, for example 20-100 volts. The voltage can attract resin ions to contact, and the resin can form the ED coating  2950  on the contact. 
     After the ED coating has been applied in act  3030 , the masking layer can be removed in act  3040 . For example, where the masking layer is wax, it can be removed using hot water. This can also help to set the ED coating on the contact. The carrier can be removed in act  3050 . The contact, such as contact  1910 , can then be inserted in a connector receptacle, such as the connector receptacle shown in  FIG. 29  above. 
     These and other embodiments of the present invention can provide a plating stack that is very hard and corrosion resistant, as well as wear resistant. Unfortunately, this hard plating stack can crack or create discontinuities when bent or stressed. This can be particularly problematic along portions of a flexible beam of a contact, which can bend when the contact is mated with a corresponding contact. As such, a contact with this hard plating stack can crack at its beam portion. These cracks can create a short corrosion path to an underlying substrate and other reactive layers in the hard plating stack, thereby accelerating corrosion of the contact. 
     Accordingly, embodiments of the present invention can provide this hard plating stack to a contacting portion of a contact and can limit or reduce the number of plating layers in the plating stack in a flexible beam area. Where a contact does not include a flexible beam portion, this hard plating stack can be used over a contacting portion and other portions of the contact. An example where this plating is used on a beam contact is shown in the following figure. 
       FIG. 31  illustrates another contact and its plating stacks according to an embodiment of the present invention. These plating stacks can provide a very hard plating stack over contacting portion  3120  of contact  3100  and a ductile plating stack over contact beam portions  3110  and  3150 . This combination can provide a very hard corrosion resistant contacting portion  3120  while also providing ductile corrosion resistant beam portions  3110  and  3150 . 
     Plating stack  3190  can be used to plate contacting portion  3120  of contact  3100 . Plating stack  3192  can be used to plate beam portion  3110  near contacting portion  3120 , while plating stack  3194  can be used to plate beam portion  3150  at an end of the beam of contact  3100 . Plating stack  3196  can be used for plating surface-mount portion  3130  of contact  3100 . Tab  3160  can provide mechanical stability and can be used to hold contact  3100  in place in a connector receptacle. For example, an insert molded portion can be formed around tab  3160 . 
     In these and other embodiments of the present invention, a substrate formed of copper or copper alloy, niobium and its alloys, tantalum and its alloys, aluminum, aluminum alloy, stainless steel, rhodium, rhodium alloy, ruthenium, ruthenium alloy, rhodium-ruthenium, rhodium-iridium, other platinum group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, silver alloy, other precious metal or its alloys, or other material, can be used for contact  3100 . 
     A leveling layer  3170  can be formed over contact  3100 . This leveling layer  3170  can be plated over contacting portion  3120 , beam portion  3110 , beam portion  3150 , and surface-mount portion  3130 . That is, leveling layer  3170  can be the first plating layer in plating stack  3190 , plating stack  3192 , plating stack  3194 , and plating stack  3196 . This leveling layer  3170  can be formed of copper or other material and can have a thickness of 1.0 micrometers, 2.0 micrometers, 3.0 micrometers, 4.0 micrometers, 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses. 
     A nickel-based layer  3172 , such as a tin-nickel, nickel-tungsten, nickel phosphate, electroless nickel, nickel based metal, palladium-nickel, nickel-copper, or other nickel based layer or other material, can be formed over the leveling layer. This nickel-based layer can be a support layer. Nickel-based support layer  3172  can be plated over contacting portion  3120 , beam portion  3110 , beam portion  3150 , and surface-mount portion  3130 . That is, nickel-based support layer  3172  can be the second plating layer in plating stack  3190 , plating stack  3192 , plating stack  3194 , and plating stack  3196 . This nickel-based support layer  3172  can have a thickness of 1.0 micrometers, 2.0 micrometers, 3.0 micrometers, 4.0 micrometers, 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses. 
     A first gold flash layer  3174  can be formed over the nickel-based support layer  3172 . First gold flash layer  3174  can be plated over contacting portion  3120 , beam portion  3110 , beam portion  3150 , and surface-mount portion  3130 . That is, first gold flash layer  3174  can be the third plating layer in plating stack  3190 , plating stack  3192 , plating stack  3194 , and plating stack  3196 . This first gold flash layer  3174  can be exposed at a surface-mount portion  3130  or other portion of contact  3100  where contact  3100  is soldered to a board or other substrate (not shown.) This first gold flash layer  3174  can have thickness of 0.02 to 0.05 micrometers, 0.05 to 0.10 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses along a length of a contact. For example, first gold flash layer  3174  can be twice as thick (or flashed twice) in either or both the beam portions  3110  and  3150  of contact  3100 . 
     A first layer of a precious-metal alloy can next be formed on contact  3100 . The first precious-metal alloy layer  3176  can be a rhodium alloy, such as rhodium-ruthenium. This layer can alternatively be formed of rhodium, ruthenium, ruthenium alloy, rhodium-iridium, other Pt group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, and silver alloy, other precious metal or its alloys. The first precious-metal-alloy layer  3176  can be plated over the contacting portion  3120  and beam portions  3110  and  3150  of contact  3100 . That is, first precious-metal-alloy layer  3176  can be the fourth plating layer in plating stack  3190 , plating stack  3192 , and plating stack  3194 . The first precious-metal-alloy layer  3176  can be omitted from plating stack  3196  over a surface-mount portion  3130  or other portion of contact  3100  where contact  3100  is soldered to a board or other substrate (not shown.) In contacting portion  3120 , the first precious-metal-alloy layer  3176  can have a thickness of 1.0 micrometers, 1.75 micrometers, 2.5 micrometers, 0.3 to 1.5 micrometers, 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses. The first precious-metal-alloy layer  3176  can have a thickness that tapers to a thinner dimension away from contacting portion  3120 . This tapering can further help to improve the ductile nature of the plating stacks  3192  and  3194 . For example, over beam portion  3110 , the first precious-metal-alloy layer  3176  can have a thickness of 0.5 micrometers, 1.25 micrometers, 1.75 micrometers, 0.5 to 1.0 micrometers, 1.0 to 2.5 micrometers, 1.5 to 3.0 micrometers, or more than 3.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses near the contacting portion, and it can have a thickness of 0.25 micrometers, 0.55 micrometers, 0.75 micrometers, 0.95 micrometers, 0.2 to 0.6 micrometers, 0.3 to 0.7 micrometers, 0.7 to 2.0 micrometers, or more than 2.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses over beam portion  3150 . 
     First gold flash layer  3174  can act as an adhesive for this first precious-metal-alloy layer  3176  in order to adhere the first precious metal alloy layer  3176  to the nickel-based support layer  3172 . A second gold flash layer  3178  can be formed over the first precious-metal-alloy layer  3176  on the contacting portion  3120  to allow adhesion of additional layers used to form the very hard plating stack  3190  over contacting portion  3120 . This second gold flash layer  3178  and the additional layers may be omitted from a beam portion  3110  and beam portion  3150  to reduce their hardness and increase their flexibility. Also, the first precious-metal-alloy layer  3176  and subsequent layers can be omitted from a surface-mount portion  3130  of contact  3100  to allow for soldering to a board or other substrate (not shown.) This second gold flash layer  3178  can have thickness of 0.02 to 0.05 micrometers, 0.05 to 0.15 micrometers, 0.15 to 0.30 micrometers, or more than 0.30 micrometers, or it can have a thickness in a different range of thicknesses. 
     A silver, palladium, or silver-palladium based layer  3180  can be formed over the second gold flash layer  3178  over contact portion  3120 . This layer can be silver and its alloys, palladium and its alloys, silver-palladium, a ternary silver-palladium-tellurium or quaternary silver-palladium-bismuth-tellurium, palladium-nickel, or other material. This silver or silver-palladium based layer  3180  can be a more reactive layer than subsequent layers formed on its surface. This more reactive layer can take the brunt of corrosive effects while protecting less reactive layers above and below it. To help ensure that this layer absorbs most of the corrosive effects, the silver or silver-palladium based layer  3180  can be formed having a number of micro-cracks or micro-pores in its structure. Further details on these micro-cracks and micro-pores can be found in co-pending U.S. patent application Ser. No. 15/942,408, filed Mar. 30, 2018, titled ELECTRICAL CONTACTS HAVING SACRIFICIAL LAYER FOR CORROSION PROTECTION, which is incorporated by reference. This silver or silver-palladium based layer  3180  can have thickness of less than 1 micrometers, less than 2 micrometers, 2.25 micrometers, 2.5 micrometers, 2.75 micrometers, 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 3.0 to 5.0 micrometers, or more than 5.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses. Plating stack  3190  can be used for contacting portions of other types of contacts as well. 
     A second precious-metal-alloy layer  3182  can be formed on contacting portion  3120  over silver or silver-palladium based layer  3180 . This second precious-metal alloy layer  3182  can be formed of the same material as the first precious-metal-alloy layer  3176 , or it can be formed of a different material. This layer can alternatively be formed of rhodium, ruthenium, ruthenium alloy, rhodium-iridium, other Pt group elements (palladium, osmium, iridium, and platinum) and their alloys, B540, B541, B563, B589, B683, B685, or B731, titanium, titanium alloy, gold, gold alloy, silver, and silver alloy, other precious metal or its alloys. The second precious-metal alloy layer  3182  can be formed of a rhodium alloy, such as rhodium-ruthenium. The second precious-metal-alloy layer  3182  can form a top plate at the surface of contacting portion  3120 . This second precious-metal-alloy layer  3182  can form a surface for the very hard plating stack  3190  on contacting portion  3120  of contact  3100 . This second precious-metal-alloy layer  3182  can have a thickness of 1.0 micrometers, 2.0 micrometers, 3.0 micrometers, 4.0 micrometers, less than 1 micrometers, less than 2 micrometers, 0.5 to 1.0 micrometers, 1.0 to 3.0 micrometers, 2.0 to 4.0 micrometers, or more than 4.0 micrometers, or it can have a different thickness or a thickness in a different range of thicknesses. 
     To avoid cracking of the plating layers at beam portions  3110  and  3150  of contact  3100 , this very hard plating stack  3190  can be limited to contacting portion  3120  of contact  3100 . Since the beam portions  3110  and  3150  of contact  3100  do not directly form electrical connections, they can be protected with a ductile nonconductive protective layer. This layer can be a nonconductive electrophoretic coating  3184  formed of a base material containing impurities. The impurities can slow corrosion by increasing a total distance corrosive elements must travel through the coating before reaching the plating stack under the electrophoretic coating. In these and other embodiments of the present invention, the base material can be acrylic resin, plastic, or other material. The impurities can be one or more of titanium dioxide, polytetrafluoroethylene, talcum, magnesium oxide, aluminum oxide, calcium oxide, or other inorganic particles. These particles can block corrosion paths through the nonconductive electrophoretic coating, thereby lengthening the corrosion path. This nonconductive electrophoretic coating  3184  can have a thickness of 2.0 to 5.0 micrometers, 3.0 to 10.0 micrometers, 3.0 to 11.0 micrometers, 5.0 to 15.0 micrometers, 10.0 to 20.0 micrometers, or more than 10.0 micrometers, or it can have a thickness in a different range of thicknesses. This electrophoretic coating  3184  can be formed in the same or similar manner as the other electrophoretic coatings described herein. 
     As with the other examples disclosed herein, one or more of these layers, such as second gold flash layer  3178 , can be omitted and one or more other layers can be added. 
       FIG. 32  illustrates a portion of a plating and coating for a contact beam according to an embodiment of the present invention. In this example, plating stack  3220  can be formed on contact beam  3210 . Electrophoretic coating  3230  can be formed on plating stack  3220 . Plating stack  3220  and electrophoretic coating  3230  can be plating stack  3192  or  3194  in  FIG. 31 , or other plating stack consistent with embodiments of the present invention. Specifically, electrophoretic coating  3230  can be electrophoretic coating  3184  in the example of  FIG. 31 . Contact beam  3210  can be beam portion  3110  or  3150  of contact  3100  in  FIG. 31 , or other contact. 
     Electrophoretic coating  3230  can be formed of acrylic resin, plastic, or other material, and can include one or more various types of impurities  3232 . These impurities one or more of titanium dioxide, polytetrafluoroethylene, talcum, magnesium oxide, aluminum oxide, calcium oxide, or other inorganic particles. The presence of these particles can act to increase a length of a corrosion path  3290  as shown. This increased length helps to protect plating stack  3220  from corrosion. Electrophoretic coating  3230  can be ductile such that it does not crack as contacting portion  3120  of contact  3100  engages corresponding contacts in corresponding connectors (not shown.) 
       FIG. 33  illustrates a side view of a connector receptacle according to an embodiment of the present invention. This connector receptacle can include an opening  2972  in housing  2970  for receiving a corresponding connector insert (not shown.) Contacts (not shown) on the corresponding connector insert can physically and electrically connect to contacting portions  3120  of contacts  3100 . Contact  3100  can further include beam portions  3110  and  3150 . Tab  3160  can be housed an injection molded portion  2990 . Surface-mount portion  3130  can be soldered to a board or other appropriate substrate. Moisture entering opening  2972  can be prevented from reaching surface-mount portion  3130  by insert molded portion  2990 . Side ground contacts  2960  can contact side contacts on the corresponding connector insert when it is inserted into this connector receptacle. Top shield  2980  can help to electrically isolate this connector receptacle. 
     In practical terms, the plating layers shown in  FIG. 31  might not have abrupt edges as shown. Instead, they can taper or merge into one another. An example is shown in the following figure. 
       FIG. 34  illustrates a side view of a top edge of a contacting portion of a contact according to an embodiment of the present invention. In this example, contacting portion  3120  and nearby beam portion  3110  of contacts  3100  can be plated with a number of layers from plating stacks  3190  and  3192  in  FIG. 31 . Plating layers  3170 ,  3172 , and  3174  are not shown for simplicity. First precious-metal-alloy layer  3176 , the first rhodium-ruthenium layer, can be formed over contacting portion  3120  and can taper to a thinner dimension along beam portion  3110 . The second gold flash layer  3178  can be formed over first precious-metal-alloy layer  3176  in contacting portion  3120 . The silver or silver-palladium based layer  3180  can be formed over the second gold flash layer  3178 . The second precious-metal-alloy layer  3182  can be formed over the silver or silver-palladium based layer  3180 , also on contacting portion  3120 . 
     Again, these layers might not extend fully over beam portion  3110  in order to provide a more ductile plating stack for that part of the contact. Accordingly, to protect this part of the contact, an electrophoretic coating  3184  can be used. Electrophoretic coating  3184  can overlap tailing portions of plating layers  3178 ,  3180 , and  3182 , as shown. This configuration can provide a very hard plating stack  3190  that is corrosion and wear resistant for contacting portion  3120 , while also providing a ductile plating stack  3192  for beam portion  3110 . 
     These and other embodiments of the present invention can reduce the rate of corrosion by using various materials as a substrate for contacts in a connector. The substrate materials can be selected from materials which can provide dimensionally stable anodes in corrosive, applied voltage electrochemical operations. A catalytically active material, also stable in the corrosive application, can be coated on top of the substrate, for example by plating. That is, the present invention can use substrate materials that provide dimensionally stable anodes that are combined with contact coating materials to form a contact in a connector that can be stable even in the presence of high voltage and corrosive environments. 
     These dimensionally stable anode materials can have electrical resistances that can be higher than copper. This can normally make them poor candidates for electrical contacts. However, where dimensions of a contact substrate are small, the increase in absolute resistance can be limited and the improved corrosion properties provide a significant enough benefit to justify the added resistance. 
     In these and other embodiments of the present invention, titanium, niobium, tantalum, zirconium, tungsten, or other dimensionally stable anode materials can be used for a substrate. These materials can also be used in alloying to modify mechanical properties without negatively impacting the applied voltage electrochemical resistance of the alloy. 
     In these and other embodiments of the present invention coating materials can include platinum, gold, ruthenium, rhodium, iridium, and palladium. In these and other embodiments of the present invention oxides of these contact coating and substrate materials can be used. Many of the selected materials form stable oxides which also can survive in highly corrosive environments. These can include titanium dioxide, ruthenium oxide, and palladium oxide. In these and other embodiments of the present invention, the contact coating materials can be used as substrate materials. When these materials are used, additional coatings can be used on the surface of the contact. 
     In a specific embodiment of the present invention, a contact used in a connector can be formed of a niobium substrate. The substrate can be coated by plating with first a platinum layer, followed by a Gold intermediate layer, and then a top contact layer of rhodium/ruthenium alloy. 
     In these and other embodiments of the present invention, the non-mating portions of the connector can be encapsulated in a sealed and liquid resistant material, such as an epoxy, so that corrosive materials cannot pass beyond the connector into corrosive materials, such as copper, present behind the corrosion resistant connector. 
     Several contacts, such as contacts  220 ,  222 ,  820 , and  1910 , are shown in particular contexts. In various embodiments of the present invention, these contacts can be used in other contexts. For example, they can be located at a surface of a device enclosure, in a connector insert, on a connector insert, in a connector receptacle, or in, or on, another contacting structure. Also, while these contacts are shown as having a particular shape, these shapes can vary in these and other embodiments of the present invention. 
     Several methods of forming contacts are shown herein, such as stamping contacts from copper or some combination of copper and a precious-metal alloy. Also, several plating stacks and methods of plating are shown, as are various form factors for contacts. In various embodiments of the present invention, each of these contacts of various form factors can be formed of copper or some combination of copper and a precious-metal alloy, or other materials, and can be plated with one or more of the various stacks shown herein. For example, contacts, such as contacts  220  can be plated using one or more of the plating stacks  430 ,  930 ,  2210 ,  2610 , or other plating stacks according to an embodiment of the present invention. Contacts such as contacts  222  can be plated using one or more of the plating stacks  430 ,  930 ,  2210 ,  2610 , or other plating stacks according to an embodiment of the present invention. Contacts such as contacts  820  can be plated using one or more of the plating stacks  430 ,  930 ,  2210 ,  2610 , or other plating stacks according to an embodiment of the present invention. Contacts such as contacts  1910  can be plated using one or more of the plating stacks  430 ,  930 ,  2210 ,  2610 , or other plating stacks according to an embodiment of the present invention. Other contacts can be plated using one or more of the plating stacks  430 ,  930 ,  2210 ,  2610 , or other plating stacks according to an embodiment of the present invention. 
     While embodiments of the present invention are well-suited to contact structures and their method of manufacturing, these and other embodiments of the present invention can be used to improve the corrosion resistance of other structures. For example, electronic device cases and enclosures, connector housings and shielding, battery terminals, magnetic elements, measurement and medical devices, sensors, fasteners, various portions of wearable computing devices such as clips and bands, bearings, gears, chains, tools, or portions of any of these, can be covered with a precious-metal alloy and plating layers as described herein and otherwise provided for by embodiments of the present invention. The precious-metal alloy and plating layers for these structures can be formed or manufactured as described herein and otherwise provided for by embodiments of the present invention. For example, magnets and other structures for fasteners, connectors, speakers, receiver magnets, receiver magnet assemblies, microphones, and other devices can have their corrosion resistance improved by structures and methods such as those shown herein and in other embodiments of the present invention. 
     In these and other embodiments of the present invention, including the above contacts, other layers, such as barrier layers to prevent corrosion of internal structures can be included. For example, barrier layers, such as zinc barrier layers, can be used to protect magnets or other internal structures from corrosion by cladding or plating layers. Catalyst layers can be used to improve the rate of deposition for other layers, thereby improving the manufacturing process. These catalyst layers can be formed of palladium or other material. Stress separation layers, such as those formed of copper, can also be included in these and other embodiments of the present invention, including the above contacts. Other scratch protection, passivation, and corrosion resistance layers can also be included. 
     In various embodiments of the present invention, the components of contacts and their connector assemblies can be formed in various ways of various materials. For example, contacts and other conductive portions can be formed by stamping, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions can be formed of stainless steel, steel, copper, copper titanium, phosphor bronze, palladium, palladium silver, or other material or combination of materials. They can be plated or coated with nickel, gold, or other material. The nonconductive portions, such as the housings and other portions, can be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions can be formed of silicon or silicone, Mylar, Mylar tape, rubber, hard rubber, plastic, nylon, elastomers, liquid-crystal polymers (LCPs), ceramics, or other nonconductive material or combination of materials. 
     Embodiments of the present invention can provide contacts and their connector assemblies that can be located in, and can connect to, various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, wearable computing devices, cell phones, smart phones, media phones, storage devices, keyboards, covers, cases, portable media players, navigation systems, monitors, power supplies, adapters, remote control devices, chargers, and other devices. These contacts and their connector assemblies can provide pathways for signals that are compliant with various standards such as Universal Serial Bus (USB), High-Definition Multimedia Interface (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt, Lightning, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. In various embodiments of the present invention, these interconnect paths provided by these connectors can be used to convey power, ground, signals, test points, and other voltage, current, data, or other information. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20190909
Publication Date: 20210504
Grant Date: 20210504
Priority Date: 20160318
Inventors: Esmaeili, Hani
BAGWELL, KENNETH MICHAEL
UBELLACKER, HOLLY
LIU, JUDY HSIEN-CHIH
JOL, ERIC S.
BITTERLICH, CHRISTOPH
BARNSTEAD, MICHAEL W.
WERNER, CHRISTOPH
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R12/57", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R24/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R43/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/035", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/035", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R43/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/035", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 69055447