PATENT DOCUMENT

Publication Number: US-10411379-B2
Application Number: US-201715464051-A
Country: US
Kind Code: B2

Title: Precious-metal-alloy contacts

Abstract:
Contacts that may be highly corrosion resistant, may be readily manufactured, and may conserve precious materials. One example may provide contacts having a layer of a precious-metal alloy to improve corrosion resistance. The precious-metal-alloy layer may 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 may 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. An electronic device comprising:
 a connector receptacle comprising: 
 a housing; and 
 a plurality of contacts supported by the housing; each contact comprising:
 a beam comprising a first material; and 
 a contacting portion welded to the beam and comprising a second material consistent with one of ASTM Standards B540, B563, B589, B683, B685, or B731. 
 
 
     
     
       2. The electronic device of  claim 1  wherein the second material is consistent with ASTM Standard B540. 
     
     
       3. The electronic device of  claim 1  wherein the second material is consistent with ASTM Standard B685. 
     
     
       4. The electronic device of  claim 1  wherein each of the plurality of contacts comprises a surface-mount contact portion, the surface-mount contact portion of each of the plurality of contacts attached to a board of the electronic device. 
     
     
       5. The electronic device of  claim 4  further comprising a nonconductive coating partially covering the beam such that at least a portion of the contacting portion is exposed. 
     
     
       6. The electronic device of  claim 5  wherein the surface-mount contact portion of each of the plurality of contacts is not covered by the nonconductive coating. 
     
     
       7. The electronic device of  claim 6  wherein the beam of each of the plurality of contacts is formed primarily of copper. 
     
     
       8. The electronic device of  claim 7  further comprising a plurality of plating layers over the beam, wherein the plurality of plating layers comprises a leveling layer over the beam, a first adhesion layer over the leveling layer, a barrier layer over the first adhesion layer, a second adhesion layer over the barrier layer, and a top plate over the second adhesion layer. 
     
     
       9. The electronic device of  claim 8  wherein the first adhesion layer and the second adhesion layer are formed of gold, the barrier layer comprises one of tin-copper, nickel, palladium, or silver, and the top plate comprises one of copper, gold, rhodium-ruthenium, gold-palladium, dark ruthenium, dark palladium, or gold-copper. 
     
     
       10. A connector insert comprising:
 a ground ring around an opening; 
 a plurality of contacts located in the opening; 
 an overmold formed around the plurality of contacts in the opening such that contacting surfaces of each of the plurality of the contacts are exposed, each of the plurality of contacts comprising:
 a substrate having a top surface; 
 a layer of high-entropy material clad to the top surface of the substrate, wherein the layer of high-entropy material comprises a material consistent with one of ASTM Standards B540, B563, B589, B683, B685, or B731; and 
 a plurality of plating layers plated over the layer of high-entropy material and including a top plate to form the contacting surface. 
 
 
     
     
       11. The connector insert of  claim 10  wherein the layer of high-entropy material extends at least partially along sides of each of the plurality of contacts. 
     
     
       12. The connector insert of  claim 10  wherein each of the plurality of contacts comprises a narrow portion attached to a printed circuit board. 
     
     
       13. The connector insert of  claim 12  wherein the high-entropy material comprises a material consistent with ASTM Standard B540. 
     
     
       14. The connector insert of  claim 10  wherein the plurality of plating layers further comprises a first adhesion layer over the layer of high-entropy material, a barrier layer over the first adhesion layer, a second adhesion layer over the barrier layer, and a top plate over the second adhesion layer. 
     
     
       15. The connector insert of  claim 14  wherein the top plate comprises one of copper, gold, rhodium-ruthenium, gold-palladium, dark ruthenium, dark palladium, or gold-copper. 
     
     
       16. The connector insert of  claim 15  wherein the first adhesion layer and the second adhesion layer are formed of gold and the barrier layer comprises one of tin-copper, nickel, palladium, or silver. 
     
     
       17. An electronic device comprising:
 a connector receptacle comprising: 
 a housing; and 
 a plurality of contacts supported by the housing; each contact comprising: 
 a beam having a contacting area near an end of the beam; 
 a nonconductive electrophoretic coating over the beam such that the contacting area of the beam is exposed; and 
 a plurality of plating layers over the beam, wherein the plurality of plating layers comprises a leveling layer over the beam, a first adhesion layer over the leveling layer, a barrier layer over the first adhesion layer, a second adhesion layer over the barrier layer, and a top plate over the second adhesion layer, wherein leveling layer comprises one of a nickel-tungsten alloy or nickel alloy, the first adhesion layer and the second adhesion layer are formed of gold, and the barrier layer comprises one of tin-copper, nickel, palladium, silver, nickel-tungsten, or nickel alloy. 
 
     
     
       18. The electronic device of  claim 17  wherein the beam is formed primarily of copper. 
     
     
       19. The electronic device of  claim 17  wherein the top plate comprises one of copper, gold, rhodium-ruthenium, gold-palladium, dark ruthenium, dark palladium, or gold-copper. 
     
     
       20. The electronic device of  claim 17  wherein each of the plurality of contacts comprises a surface-mount contact portion. 
     
     
       21. The electronic device of  claim 20  wherein the surface-mount contact portion is not covered by the nonconductive electrophoretic coating.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. patent application Ser. No. 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 may be conveyed over cables that include a connector insert at each end of a cable. The connector inserts may be inserted into receptacles in the communicating electronic devices. In other electronic systems, contacts on a first device may be in direct contact with contacts on a second device without the need for an intervening cable. In such systems, a first connector may be formed as part of the first electronic device and a second connector may be formed as part of the second electronic device. 
     The contacts in these various connectors may be exposed to liquids and fluids that may 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 may cause one or more contacts to corrode, particularly where a voltage is present on the one or more contacts. This corrosion may impair the operation of the electronic device or cable and in severe cases may render the device or cable inoperable. Even where operation is not impaired, corrosion may 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 may be readily apparent to a user and it may create a negative impression in the mind of a user that may 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 may therefore be manufactured in great numbers. Therefore it may be desirable that these contacts be readily manufactured such that demand for the devices may be met. It may also be desirable to reduce the consumption of rare or precious materials. 
     Thus, what is needed are contacts that may be highly corrosion resistant, may be readily manufactured, and may conserve precious materials. 
     SUMMARY 
     Accordingly, embodiments of the present invention may provide contacts that may be highly corrosion resistant, may be readily manufactured, and may conserve precious materials. These contacts may be located at a surface of an electronic device, at a surface of a connector insert, or 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 may provide connector contacts that include a layer or portion formed of a precious-metal alloy to improve corrosion resistance. The precious-metal-alloy layer may be plated for further corrosion resistance and wear improvement. Resources may 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 may 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 may be formed of a high-entropy material. Examples of this material may include material consistent with ASTM Standards B540, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer may 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 may 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 may be selected for use as the precious-metal alloy. In these and other embodiments of the present invention, a precious-metal-alloy layer may 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 may 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, may be formed of a precious-metal alloy. 
     In these and other embodiments of the present invention, the precious-metal-alloy layer may 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, may be formed of a precious-metal alloy. This substrate may 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 may 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 may be selected for use to form the contact substrate. The material may 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 may 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 may form the majority of the contact and may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a diffusion or bonding layer may be formed when the precious-metal alloy is bonded or clad to the substrate. This bonding layer may be an intermetallic bond of the precious-metal alloy and the alloy of the substrate. This diffusion or bonding layer may 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 may be placed between the precious-metal-alloy layer and the substrate. These intermediate layers may have better corrosion resistance than copper and may also be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers may be formed using titanium, steel, tantalum, or other material. This material may 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 may be plated with a hard, durable, wear and corrosion resistant plating stack. This stack may be formed of one or more plating layers. 
     A first plating layer may be plated over the precious-metal-alloy layer for leveling and adhesion. For example, gold, copper, or other material may act as a leveler and tend to fill vertical differences across a surface of the precious-metal-alloy layer. This may help to cover defects in the substrate, such as nodules or nodes that may be left behind by an electropolish or chemical polishing step. This first plating layer may 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 may 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 may be omitted. This first plating layer may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a top plate may be plated over the first plating layer. The top plate may 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 may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce its corrosion. The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. This top plate may 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 may 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 may be plated over the first plating layer. The second plating layer may 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 may be chosen on this basis. In these and other embodiments of the present invention, the second plating layer may be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material may provide a second plating layer that is more positively charged than a top plate of rhodium ruthenium, rhodium, or other material. This may cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This second plating layer may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the first plating layer may be omitted and the second plating layer may be plated directly on the precious-metal layer. 
     In these and other embodiments of the present invention, a third plating layer may be plated over the second plating layer. The third plating layer may, like the first plating layer, provide leveling and adhesion. For example, gold may tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and may provide adhesion between the second plating layer and a top plate. For example, a gold plating layer may provide adhesion between a second plating layer of palladium and a top plate of rhodium ruthenium. The gold layer may be a plated gold strike. Instead of gold, the third plating layer may be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the third plating layer may be omitted and the top plate may be plated directly on the second plating layer. 
     In these and other embodiments of the present invention, the top plate described above may be plated over the third plating layer. 
     In these and other embodiments of the present invention, the plating materials used may be selected based a desire to conserve precious resources, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     These contacts may 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 may at least partially cover a layer of substrate material. As described herein, one or more intermediate layers may be placed between the layer of precious-metal alloy and the substrate. Contacts may be stamped such that a precious-metal-alloy layer may be clad to a bulk or substrate layer, or over the bulk or substrate layer with one or more intermediate layers. The materials used may be heated (and possibly annealed) and elongated during the stamping. For example, a 35, 50, or 70 percent elongation may be used. 
     In these and other embodiments of the present invention, carriers may be stamped of the bulk material. These carriers may 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 may 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 may be formed in the layer of bulk or substrate material and the layer of precious-metal alloy may be placed in the one or more grooves. In these and other embodiments of the present invention, one or more of the grooves may be deeper than one or more of the remaining grooves. In this way a layer of precious-metal alloy in a contact may have a greater depth along at least a portion of the sides of the contact. This may help to improve corrosion resistance along sides of the resulting contacts. 
     In these and other embodiments of the present invention, contacts may be formed in other ways and have different plating layers. For example, strips of a copper alloy or other material may 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 may 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 may also be stamped such that only portions, such as a contacting portion, may be formed of the precious-metal alloy while the remainder of the contact and a carrier may be formed of the copper alloy or other material in order to conserve resources. 
     These and other embodiments of the present invention may include various plating layers at a contacting portion or other portion of a contact. In one example a contact substrate may 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 may be used to removing stamping burrs, which could otherwise expose nickel silicides or other particles in the substrate. Unfortunately, the electropolish step may leave nodules on the contact surface. Chemical polish may be used in its place, though that may leave nodes behind on the contact surface. 
     Accordingly, a first plating layer to provide a surface leveling may be plated on the substrate. This first plating layer may be copper or other material, such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, and it may 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 may be sufficient and an electropolish step may be omitted. The first plating layer may also provide adhesion between the substrate and a second plating layer that may be plated over the first plating layer. The first plating layer may 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 may have a thickness in a different range of thicknesses. 
     Cracks in these plating layers may provide pathways for fluids that may cause corrosion. Accordingly, a second, harder plating layer to prevent layers above the second plating layer from cracking may be plated over the first plating layer. This second plating layer may be formed of an electroless nickel composite. This second plating layer may 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 may have a thickness in a different range of thicknesses. In various embodiments of the present invention, this second layer may be omitted. 
     A third plating layer may work in conjunction with the second plating layer. The third plating layer may be plated over the second plating layer. This third plating layer may be soft to absorb shock and thereby minimize cracking in the layers above the third plating layer. The third plating layer may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer may provide adhesion between its neighboring layers and may provide a leveling effect as well. This third plating layer may 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 may have a thickness in a different range of thicknesses. In various embodiments of the present invention, these second and third plating layers may be omitted, or the second layer may be omitted, though other layers may be added or omitted as well. 
     A fourth plating layer to provide corrosion resistance may be plated over the third plating layer. The fourth plating layer may act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the fourth plating layer may be chosen on this basis. This layer may be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material may provide a second plating layer that is more positively charged than a top plate of rhodium ruthenium, rhodium, or other material. This may cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer may be somewhat harder than a fifth plating layer above it, which may prevent layers above the fourth plating layer from cracking when exposed to pressure during a connection. The fourth plating layer may 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 may have a thickness in a different range of thicknesses. When palladium is used, it may 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 may be plated over the fourth plating layer. The fifth plating layer may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The fifth plating layer may provide further leveling as well. The fifth plating layer may 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 may have a thickness in a different range of thicknesses. 
     A top plate may be formed over the fifth plating layer. The top plate may be highly corrosive and wear resistant. This layer may be thinned in high-stress locations to reduce the risk of cracking. The top plate may 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 may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce its corrosion. The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate may 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 may have a thickness in a different range of thicknesses. 
     In various embodiments of the present invention, these layers may be varied. For example, the top plate may 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 may 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, may be omitted. 
     In these and other embodiments of the present invention, one or more plating layers may be applied at a varying thickness along a length of the contact. In these embodiments, drum plating may be used. A contact on a carrier may be aligned with a window on an outside drum though which physical vapor deposition or other plating may occur. The window on the outside drum may have an aperture that is varied during rotation by an inside drum, the inside drum inside the outside drum. 
     These contacts may each have a high wear contacting portion to mate with a contact in a corresponding connector. They may 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 may 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 may be used to removing stamping burrs, though they may leave nodules or nodes on the contact surface. 
     Accordingly, a first plating layer to provide a surface leveling may be plated on the substrate. This first plating layer may be copper or other material such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, or other material, and it may 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 may be sufficient and an electropolish step may be omitted. This first plating layer may also provide adhesion between its neighboring substrate and second plating layer. The first plating layer may 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 may have a thickness in a different range of thicknesses. 
     A second plating layer to provide corrosion resistance may be plated over first plating layer. The second plating layer may act as a barrier layer to prevent color leakage to the surface of the contact, and the material used for the second plating layer may be chosen on this basis. This second plating layer may be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material may provide a second plating layer that is more positively charged than a top plate of rhodium ruthenium, rhodium, or other material. This may cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer may be somewhat harder than a third plating layer above it, which may prevent layers above the third plating layer from cracking when exposed to pressure during a connection. The second plating layer may have a thickness that varies along a length of the contact. For example, it may 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 may have a thickness in a different range of thicknesses along a length of a contact. The second plating layer may be thicker near a high-wear contacting portion, and it may 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 may be plated over the second plating layer. The third plating layer may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer may also provide a leveling effect. The third plating layer may 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 may have a thickness in a different range of thicknesses along a length of a contact. 
     A top plate may be formed over the third plating layer. The top plate may be highly corrosive and wear resistant. This top plate may be thinned in the high-stress beam portion to reduce the risk of cracking. The top plate may 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 may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce its corrosion. The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate may 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 may have a thickness in a different range of thicknesses. Again, the top plate may be omitted from the surface-mount or through-hole contacting portion. The top plate may be thicker near a high-wear contacting portion, and it may thin away from the high-wear region. 
     In these and other embodiments of the present invention, other layers may be formed on contacts to prevent wear and corrosion. For example, a plastic insulating layer may be formed using electroplastic deposition or electro deposition (ED). This layer may cover portion of a contact to prevent corrosion. A contacting portion of the contact may remain exposed such that it may form an electrical connection with a contact in a corresponding connector. Also, a surface-mount or through-hole contact portion may remain exposed such that it may be soldered to a corresponding contact on a board or other appropriate substrate. 
     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 may 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, may 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 may 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 may 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 may be formed in various ways of various materials. For example, contacts and other conductive portions may be formed by stamping, coining, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions may 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 may be plated or coated with nickel, gold, palladium, or other material, as described herein. The nonconductive portions, such as the housings and other portions, may be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions may 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 may provide contacts and their connector assemblies that may be located in, or may 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 may 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 may be used to convey power, ground, signals, test points, and other voltage, current, data, or other information. 
     Various embodiments of the present invention may incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention may 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 may 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 may 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 may 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 may be stamped to form contacts according to an embodiment of the present invention; 
         FIG. 19  illustrates a pattern that may be employed in stamping contacts according to an embodiment of the present invention; 
         FIG. 20  illustrates another pattern that may be employed in stamping contacts according to an embodiment of the present invention; 
         FIG. 21  illustrates another pattern that may 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 may 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 may 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; and 
         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. 
     
    
    
     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  may be connected to accessory device  120  in order to share data, power, or both. Specifically, contacts  220  on host device  110  may be electrically connected to contacts  222  on accessory device  120 . Contacts  220  on host device  110  may 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  may 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  may be located on the surfaces of their respective devices. But this location may make them vulnerable to exposure to liquids or other fluids. This exposure, particularly when there are voltages present on the exposed contacts, may lead to their corrosion. This corrosion may mar the contacts and may be readily apparent to a user. This corrosion may lead to a reduction in operation of the device and may even render the device inoperable. Even when such corrosion does not reach the level of device impairment, it may create a negative impression in the mind of a user that may reflect poorly on the device and the device&#39;s manufacturer. 
     Accordingly, embodiments of the present invention may provide contacts that may be highly corrosion resistant. But ordinarily, such an increase in corrosion resistance may lead to a reduction in manufacturability. Accordingly, embodiments of the present invention may provide contacts that are readily manufactured and may 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 an enclosure  210 . Contacts  210  may be insulated from device enclosure  210  by contact assembly housing  230 . In other embodiments of the present invention, for example where housing  210  is nonconductive, the insulation provided by contact assembly housing  230  may not be needed and contact assembly housing  230  may be omitted. In still other embodiments of the present invention, contacts  220  may 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  may 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  may have various shapes or contours. For example, housing  210  may be flat, curved, or have other shapes. Surfaces of contacts  220  may 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, housing  210  portions may 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 may be employed and one or more of these contacts may 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  may be located in a contact housing  230 . In various embodiments of the present invention, undersides of contacts  220  may 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 contact assembly housing  230 . Contact  220  may include bulk or substrate layer  410 . Contact  220  may have a primarily disk-shape, though contact  220  may have other shapes consistent with embodiments of the present invention. Bulk or substrate layer  410  may include narrow portion  422 , which may be electrically connected by solder region  450  to board  440 . Board  440  may be a flexible circuit board, printed circuit board, or other appropriate substrate. Board  440  may connect to electrical or mechanical, components in the electronic device housing contact  220 . In this way, power and signals may be transferred between this electronic device and a second electronic device via contacts  220 . 
     Contact  220  may include bulk or substrate layer  410 . The resources consumed by contact  220  may 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  may 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 may be selected for use to form the bulk or substrate layer  410 . The material may 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 may 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  may form the majority of the contact and may 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 may have a thickness in a different range of thicknesses. 
     Bulk or substrate layer  410  may be clad by a precious-metal-alloy layer  420 . Precious-metal-alloy layer  420  may be a high entropy material, such as materials consistent with ASTM Standards B540, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer  420  may 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 may be selected for use as the precious-metal alloy. In various embodiments of the present invention, the precious-metal-alloy layer  420  may 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  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, one or more intermediate layers may be placed between the precious-metal-alloy layer  420  and the bulk or substrate layer  410 . These intermediate layers may have better corrosion resistance than copper and may be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers may be formed using titanium, steel, tantalum, or other material. This material may be selected based on its availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     Cladding or precious-metal-alloy layer  420  may be plated by one or more plating layers, shown here as plating stack  430 . Plating stacks, such as plating stack  430  may 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  may 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 may be used to plate a contacting surface of a contact according to an embodiment of the present invention. This plating stack  430  may include a first plating layer  510  that may be plated over the precious-metal-alloy layer  420  as shown in  FIG. 4  for leveling and adhesion. For example, gold may tend to fill vertical differences across a surface of the precious-metal-alloy layer  420 . These vertical differences may include nodes and nodules that may be left behind by electropolishing and chemical polishing performed on the underlying material. First plating layer  510  may also provide adhesion between the precious-metal-alloy layer  420  and a second plating layer  520 . Instead of gold, first plating layer  510  may be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This first plating layer  510  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, the first plating layer  510  may be omitted and the second plating layer  520  may be plated directly on the precious-metal layer. 
     In these and other embodiments of the present invention, a second plating layer  520  may be plated over first plating layer  510 . Second plating layer  520  may 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  may be chosen on this basis. In these and other embodiments of the present invention, second plating layer  520  may be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material may provide a second plating layer  520  that is more positively charged than a top plate  540  of rhodium ruthenium, rhodium, or other material. This may 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  may be somewhat harder than a third plating layer  530  above it, which may prevent layers above the third plating layer  530  from cracking when exposed to pressure during a connection. This second plating layer  520  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a third plating layer  530  may be plated over second plating layer  520 . Third plating layer  530  may, like first plating layer  510 , provide leveling and adhesion. For example, gold may tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and may provide adhesion between second plating layer  520  and a top plate  540 . Instead of gold, third plating layer  530  may be formed of nickel, palladium, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer  530  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, top plate  540  may be plated over third plating layer  530 . Top plate  540  may 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  may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  540  may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce the corrosion of top plate  540 . The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. Top plate  540  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, third plating layer  530  may be omitted and top plate  540  may be plated directly on second plating layer  520 . 
     In these and other embodiments of the present invention, top plate  540  may be plated directly over first plating layer  510  and second and third plating layers  520  and  530  may be omitted. 
     In these and other embodiments of the present invention, the plating materials used may 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 may 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 may 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  may be at least partially covered by a layer of precious-metal alloy  420 . These layers may be provided in rolls  610 . Rolls  610  may be stamped or coined to form contacts  220 . Carriers  620 , attached to contacts  220 , may similarly be stamped. Carriers  620  may be used to manipulate contacts  220  during later processing steps such as blasting, polishing, etching, annealing, or other processing steps. Contacts  220  may be stamped in a manner to efficiently utilize the precious-metal alloy  420 . Unused material from precious-metal layers, such as precious-metal layer  420 , and bulk or substrates, such as bulk or substrate  410 , may be recycled or otherwise reused. 
     It may be very difficult to plate bulk or substrate layer  410  with a precious-metal alloy  420 . Accordingly, in this embodiment of the present invention, contacts  220  may be stamped from bulk or substrate layer  410  and precious-metal-alloy layer  420 . This stamping process may be coining or other type of process. This stamping process may bond the precious-metal-alloy layer  420  to the bulk or substrate layer  410 . This stamping process may be done at an elevated temperature (which may be used for annealing.) The material of roll  610  may 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 may be used. 
     In these and other embodiments of the present invention this diffusion or bonding layer may be formed when the precious-metal alloy is bonded or clad to the substrate. This bonding layer may be an intermetallic bond of the precious-metal alloy  420  and the alloy of the bulk or substrate layer  410 . This diffusion or bonding layer may 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 may 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  may include a bulk or substrate layer  410  having a narrow portion  422 . Narrow portion  422  may be soldered to a flexible circuit board, printed circuit board, or other appropriate substrate. Bulk or substrate layer  410  may be clad with a precious-metal-alloy layer  420 . Tail portion  710  may remain after carrier  620  has been broken away or otherwise physically disconnected from contact  220 . After stamping, contact  220  may 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 may 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 may be used in a connector insert or connector receptacle are shown in the following figures. These and other embodiments of the present invention may be used as contacts on a surface of a device or elsewhere as shown above as well. 
       FIG. 8  illustrates a connector insert that may be improved by the incorporation of an embodiment of the present invention. In this example, a connector insert may include a ground ring  810  surrounding an opening  830  for contacts  820 . Contacts  820  may 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  may 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 may 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  may include a bulk or substrate layer  910 . Bulk or substrate layer  910  may terminate in a narrow portion  912 . Narrow portion  912  may be electrically connected through solder  960  to a contact on board  970 , which may be a flexible circuit board, printed circuit board, or other appropriate substrate. Areas  950  below portions of bulk or substrate layer  910  may include air gaps to reduce side-to-side capacitance between contacts  820 . Board  970  may connect to conductors or electrical or mechanical, components in the connector insert housing contact  820 . In this way, power and signals may be transferred between a first electronic device and a second electronic device via contacts  820 . 
     Bulk or substrate layer  910  may be clad by precious-metal-alloy layer  920 . Precious-metal-alloy layer  920  may be plated by plating layer  930 . Plating layer  30  may extend along sides of the contact shown as regions  933 . Regions  933  may be omitted or may extend along other portions of the underside of contact  820 . Contact  820  may 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  may 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  may 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 may be selected for use to form bulk or substrate layer  910 . The material may 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  may 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  may form the majority of the contact and may 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 may have a thickness in a different range of thicknesses. 
     Bulk or substrate layer  910  may be may be clad by a precious-metal-alloy layer  920 . Precious-metal-alloy layer  920  may be a high entropy material, such as materials consistent with ASTM Standards B540, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer  920  may 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 may be selected for use as the precious-metal alloy. In various embodiments of the present invention, the precious-metal-alloy layer  920  may 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  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, one or more intermediate layers may be placed between precious-metal-alloy layer  920  and the bulk or substrate layer  910 . These intermediate layers may have better corrosion resistance than copper and may also be more readily available than the material used as the precious-metal alloy. The one or more intermediate layers may be formed using titanium, steel, tantalum, or other material. This material may be selected based on its availability, formability, elongation, hardness, conductivity, ability to be stamped, or other property. 
     Cladding or precious-metal-alloy layer  920  may be plated by one or more plating layers, shown here as plating stack  930 . Plating stack  930  may be used to provide a color match, or desired color mismatch, with ground ring  810  as shown in  FIG. 8 . Plating stack  930  may 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 may be used to plate a contacting surface of a contact according to embodiments of the present invention. This plating stack  930  may include a first plating layer  1010  that may be plated over the precious-metal-alloy layer  920  as shown in  FIG. 9  for leveling and adhesion. For example, gold may tend to fill vertical differences across a surface of the precious-metal-alloy layer  920 . These vertical differences may include nodes and nodules that may be left behind by electropolishing and chemical polishing performed on the underlying material. First plating layer  1010  may also provide adhesion between the precious-metal-alloy layer  920  and a second plating layer  1020 . Instead of gold, the first plating layer  1010  may be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This first plating layer  1010  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, a second plating layer  1020  may be plated over first plating layer  1010 . Second plating layer  1020  may 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 may be chosen on that basis. In these and other embodiments of the present invention, the second plating layer  1020  may be formed using nickel, palladium, tin-copper, silver, or other appropriate material. The use of palladium or other material may provide a second plating layer  1020  that is more positively charged than a top plate  1040  of rhodium ruthenium, rhodium, or other material. This may 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  may be somewhat harder than a third plating layer  1030  above it, which may prevent layers above the third plating layer  1030  from cracking when exposed to pressure during a connection. This second plating layer  1020  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, first plating layer  1010  may be omitted and second plating layer  1020  may be plated directly on precious-metal-alloy layer  920 . 
     In these and other embodiments of the present invention, a third plating layer  1030  may be plated over second plating layer  1020 . Third plating layer  1030  may, like first plating layer  1010 , may provide leveling and adhesion. For example, gold may tend to fill vertical differences across a surface of the second plating layer, the barrier layer, and may provide adhesion between second plating layer  1020  and a top plate  1040 . Instead of gold, third plating layer  1030  may be formed of nickel, copper, tin, tin copper, hard gold, gold cobalt, or other material. This third plating layer  1030  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, top plate  1040  may be plated over third plating layer  1030 . Top plate  1040  may 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  may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce the corrosion of top plate  540 . The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may 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  may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  1040  may 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 may have a thickness in a different range of thicknesses. 
     In these and other embodiments of the present invention, third plating layer  1030  may be omitted and top plate  1040  may be plated directly on second plating layer  1020 . 
     In these and other embodiments of the present invention, top plate  1040  may be plated directly over first plating layer  1010  and either or both plating layers  1020  and  1030  may be omitted. 
     In these and other embodiments of the present invention, the plating materials used may 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 may 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 may 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  may be at least partially covered by a precious-metal-alloy layer  920 . These layers may be provided on a roll, as shown as roll  610  in  FIG. 6 . Contacts  820  may be stamped, coined, or otherwise formed in these layers. Carriers (not shown) may 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  may 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  may be stamped or coined. Carriers (not shown) may 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 may be identical to the contact shown in  FIG. 9 . Precious-metal-alloy layer  920  may extend along sides of bulk or substrate layer  910 . This may further help to reduce corrosion. Specifically, if moisture or liquid seeps between  940  and contact  820 , sides of bulk or substrate layer  910  may be exposed to corrosion. This corrosion may be reduced by the presence of side portions  922  of precious-metal-alloy layer  920 . Side portions  922  may 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  may be around all or portions of sides of bulk or substrate layer  910 . 
     Side portions  922  of precious-metal-alloy layer  920  may 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 may be used to form side regions  922 . Contacts  820  and carriers may be stamped or coined as described herein. 
     The one or more grooves in bulk or substrate layer  910  may 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  may be formed in bulk or substrate layer  910 . This groove may be formed by skiving, cutting, etching, or other appropriate method. Deeper grooves  1510  may then be formed in bulk or substrate layer  910  by skiving, cutting, etching, or other process step. The resulting grooves may 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  may be initially formed by skiving, cutting, etching, or other process in bulk or substrate layer  910 . Groove  1620  may then be formed, again by skiving, cutting, edging, or other process step. Cladding or precious-metal-alloy layer  920  may 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 may 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  may include tabs and notches  1710  and  1720 . These tabs and notches  1710  and  1720  may 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 may 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 may be formed in other ways and have different plating layers. For example, strips of a copper alloy or other material may 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 may 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 may also be stamped such that only portions, such as a contacting portion, may be 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 may be stamped to form contacts according to an embodiment of the present invention. A strip of precious-metal alloy  1820  may be butt-welded or otherwise fixed or attached to edges  1850  of copper alloy strips  1830  and  1840 . These strips may be rolled into roll  1810  for handling and manufacturing purposes. In various embodiments of the present invention, contacts may 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 may be used to handle the contacts during manufacturing, may be formed in the copper alloy strips  1830  and  1840 . In various embodiments of the present invention, the comparative width of these strips may vary. Also, the materials used may vary. For example, precious-metal alloy  1820  may be replaced with another material. Copper alloy strips  1830  and  1840  may instead be formed of copper, steel, or other material. Examples showing how contacts may 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 may be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  may be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . In this example, contacts  1910  may be stamped such that they are fully formed of precious-metal alloy  1820 . Carriers (not shown), may 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 may be good. In this embodiment the present invention, a feed direction into a stamping machine may be indicated by arrow  1920 . 
       FIG. 20  illustrates another pattern that may be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  may be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . Contacts  1910  may be stamped such that they are fully formed of precious-metal alloy  1820 . Carriers (not shown) may be formed in copper alloy strips  1830  and  1840 . With contacts  1910  in this transverse direction, material utilization may be improved over the example of  FIG. 19 , though the grain direction may not be as optimal. As before, a feed direction into a stamping machine may be indicated by arrow  1920 . 
       FIG. 21  illustrates another pattern that may be employed in stamping contacts according to an embodiment of the present invention. As before, a strip of precious-metal alloy  1820  may be butt-welded at edges  1850  to copper alloy strips  1830  and  1840 . In this example, a contacting portion  2110  of contacts  1910  may be formed of precious-metal alloy  1820 , while a remainder  2120  of contacts  1910  may be formed in the copper alloy strips  1830  and  1840 . As before, a feed direction into a stamping machine may 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 strip  1820 , may be a high entropy material, such as materials consistent with ASTM Standards B540, B563, B589, B683, B685, or B731, yellow gold, or other materials. The material for the precious-metal-alloy layer  1820  may 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 may be selected for use as the precious-metal alloy  1820 . In various embodiments of the present invention, the precious-metal-alloy layer  1820  may 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 may 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 may 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, may be plated with this plating stack  2210 . After stamping or other manufacturing step, an electropolish step may 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 may leave nodules on the contact surface. Chemical polish may be used in its place, though a chemical polish may leave nodes behind on the contact surface. 
     Accordingly, a first plating layer  2220  may be plated on the substrate to provide a surface leveling. This first plating layer  2220  may be copper or other material, such as gold, nickel, tin, tin copper, hard gold, or gold cobalt, and it may 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  may be sufficient and an electropolish step may be omitted. The first plating layer  2220  may also provide adhesion between the substrate and a second plating layer  2230  that may be plated over the first plating layer  2220 . The first plating layer  2220  may 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 may have a thickness in a different range of thicknesses. In other embodiments of the present invention, this first layer  2220  may be omitted. 
     Cracks in these plating layers may provide pathways for fluids that may cause corrosion. Accordingly, a second, harder plating layer  2230  to prevent layers above it from cracking may be plated over the first plating layer  2220 . This second plating layer  2230  may be formed of an electroless nickel composite. This second plating layer may be formed of a nickel-tungsten alloy. This second plating layer  2230  may 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 may have a thickness in a different range of thicknesses. In other embodiments of the present invention, this second layer  2230  may be omitted. 
     A third plating layer  2240  may work in conjunction with the second plating layer  2230 . The third plating layer  2240  may be plated over the second plating layer. This third plating layer  2240  may be soft to absorb shock and thereby minimize cracking in the layers above the third plating layer  2240 . The third plating layer  2240  may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer  2240  may provide adhesion between its neighboring layers and may provide a leveling effect as well. This third plating layer  2240  may 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 may have a thickness in a different range of thicknesses. In various embodiments of the present invention, these second and third plating layers  2230  and  2240  may be omitted, or the second plating layer  2230  may be omitted, though other layers may be added or omitted as well or instead. 
     A fourth plating layer  2250  to provide corrosion resistance may be plated over third plating layer  2240 . The fourth plating layer  2250  layer may 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  may be chosen on this basis. This layer may be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material may provide a fourth plating layer  2250  that is more positively charged than a top plate  2270  of rhodium ruthenium, rhodium, or other material. This may 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  may be somewhat harder than a fifth plating layer  2260  above it, which may prevent layers above the fourth plating layer  2250  from cracking when exposed to pressure during a connection. The fourth plating layer  2250  may 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 may have a thickness in a different range of thicknesses. When palladium is used, it may 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  may be plated over the fourth plating layer  2250 . The fifth plating layer  2260  may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The fifth plating layer  2260  layer may also provide further leveling. The fifth plating layer  2260  layer may 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 may have a thickness in a different range of thicknesses. 
     A top plate  2270  may be formed over the fifth plating layer  2260 . The top plate  2270  may be highly corrosive and wear resistant. This top plate  2270  may be thinned in high-stress locations to reduce the risk of cracking. Top plate  2270  may 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  may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. Top plate  2270  may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce its corrosion. The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. The top plate  2270  may 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 may have a thickness in a different range of thicknesses. 
     In various embodiments of the present invention, these layers may be varied. For example, top plate  2270  may 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  may be omitted from the surface-mount or through-hole contacting portion. In other embodiments of the present invention, other layers, such as the second and third plating layers  2230  and  2240 , may be omitted. 
     Also, in these and other embodiments of the present invention, one or more plating layers may be applied at a varying thickness along a length of the contact. In these embodiments, drum plating may be used. A contact on a carrier may be aligned with a window on a first drum though which physical vapor deposition or other plating step may occur. The window on the first drum may 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 may be used in plating a contact according to an embodiment of the present invention. In this example, an outside drum  2310  may have a number of windows  2320  around an outside edge. Contacts on a carrier (as shown in  FIG. 27 ) may be aligned to each window  2320 . The outside drum  2310  may rotate and a plating layer may be formed on the contacts. The aperture of each window  2320  may vary during rotation and may 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 may 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 ) may 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) may be plated. As the inside drum rotates relative to the outside drum  2310 , an obstructing portion  2410  between windows  2330  on the inside drum may progressively block window  2320 . This narrowing aperture may be indicated as  2321  and  2322  in this figure. An example of a contact that may be plated using this dual-drum apparatus is shown in the following figure. 
       FIG. 25  illustrates a contact that may be plated according to an embodiment of the present invention. Contact  1910  may have a high-wear contacting portion  2510  to mate with a contact in a corresponding connector. Contact  1910  may 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  may 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 may act as a pathway for moisture seepage and thus corrosion. 
     Contacts, such as contacts  1910 , may be located in a connector receptacle, a connector insert, or elsewhere in a connector system. 
     A substrate for contact  1910  may 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 may be used to removing stamping burrs, though they may leave nodules or nodes on the contact surface. Again, this contact  1910  may 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  may include four layers, though in various embodiments of the present invention, there may be less than four or more than four layers. A first plating layer  2620  to provide a surface leveling may be plated on the substrate. This first plating layer  2620  may 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  may 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  may be sufficient and an electropolish step may be omitted. This first plating layer  2620  may also provide adhesion between its neighboring substrate and second plating layer  2630 . First plating layer  2620  may 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 may have a thickness in a different range of thicknesses. 
     A second plating layer  2630  to provide corrosion resistance may be plated over first plating layer  2620 . The second plating layer  2630  may 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  may be chosen on this basis. This second plating layer  2630  may be formed of palladium or other material such as nickel, tin-copper, or silver. The use of palladium or other material may provide a second plating layer  2630  that is more positively charged than a top plate  2650  of rhodium ruthenium, rhodium, or other material. This may cause the top plate to act as a sacrificial layer, thereby protecting the underlying palladium. This layer may be somewhat harder than a third plating layer  2640  above it, which may prevent layers above the second plating layer  2630  from cracking when exposed to pressure during a connection. The second plating layer  2630  may have a thickness that varies along a length of the contact. For example, it may 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 may have a thickness in a different range of thicknesses along a length of a contact. The second plating layer  2630  may be thicker near a high-wear contacting portion, and it may thin away from the high-wear region. This may 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  may be plated over the second plating layer  2630 . The third plating layer  2640  may be gold or other material such as copper, nickel, tin, tin copper, hard gold, or gold cobalt. The third plating layer may also provide a leveling effect. The third plating layer  2640  may 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 may have a thickness in a different range of thicknesses along a length of a contact. 
     A top plate  2650  may be formed over the third plating layer. The top plate  2650  may be highly corrosive and wear resistant. This top plate  2650  may be thinned in the high-stress beam portion  2930  of contact  1910  (as shown in  FIG. 25 ) to reduce the risk of cracking. The top plate  2650  may 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  may have a Vickers hardness below 100, between 100-200, between 200-300, over 300, or a hardness in another range. The top plate  2650  may be formed using rhodium ruthenium, dark rhodium, dark ruthenium, gold copper, or other alternatives. The use of rhodium ruthenium or rhodium may help oxygen formation, which may reduce its corrosion. The percentage of rhodium may be between 85 to 100 percent by weight, for example, it may be 95 or 99 percent by weight, where the most or all of the remaining material is ruthenium. This material may be chosen for its color, wear, hardness, conductivity, scratch resistance, or other property. Top plate  2650  may 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 may have a thickness in a different range of thicknesses. Again, top plate  2650  may 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  may be attached to a carrier  2710 . A roll direction may be indicated by arrow  2720 . 
     In these and other embodiments of the present invention, other layers may 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  may be formed using electrophoretic deposition (ED) or other appropriate method. This layer or coating  2850  may cover portion of a contact  1910 , primarily beam  2810 , to prevent corrosion. A contacting portion  2820  of contact  1910  may remain exposed such that it may form an electrical connection with a contact in a corresponding connector. Also, a surface-mount  2830  or through-hole contact portion (not shown) may remain exposed such that it may 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 may include a number of contacts  1910  supported by a housing  2970 . Housing  2970  may include a front opening  2972  for accepting a connector insert (not shown) and may be at least partially surrounded by top shield  2980  and bottom shield  2982 . Side ground contact  2960  may contact a shield of the connector insert when the connector insert is inserted into the connector receptacle. 
     Each contact  1910  may include beam  2910 , contacting portion or area  2920 , surface-mount contact portion  2830 , and mechanical stabilizing portion  2940 . Contacting portion or area  2920  may mate with a contact in a corresponding connector insert when the connector insert is inserted into the connector receptacle. Surface-mount contact portion  2830  may 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  may be molded or inserted into housing  2970  to fix contact  1910  in place in the connector receptacle. 
     Beam  2910  may deflect when a connector insert is inserted into the connector receptacle. This deflection may make the beam more susceptible to cracking due to corrosion. This effect may be referred to as stress corrosion cracking. Similarly, the effects of corrosion may be more severe at the beam due to this defection. That is, there may 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 may destroy or damage contact  1910 . In some contacts, plating on base of beam  2910  may crack and fatigue, and this may cause corrosion to accelerate. 
     Accordingly, these and other embodiments of the present invention may use electrophoretic deposition (ED) or other appropriate method to form ED coating  2950  to protect beam portion  2910  from corrosion. This electrophoretic deposition may form a nonconductive coating, though in these and other embodiments of the present invention, the coating may be conductive or partially conductive. In these and other embodiments of the present invention, the electrophoretic deposition process used may be an electrocoating, cathodic or anodic electrodeposition, electroplastic deposition, electro deposition, electrophoretic coating, electrophoretic painting, or other appropriate process. 
     Contact  1910  may be formed in various ways. For example, contact  1910  may have either or both contacting area  2920  and surface mount contact portion  2930  covered by a masking layer. The masking layer may be wax, paraffin, or other material. This material may be applied mechanically, by printing, such as with an ink jet, roller, pad, or other applicator, or by other method. 
     Contact  1910  may then be coated with ED coating  2950 . In these and other embodiments of the present invention, the coating material may be an acrylic resin, plastic, or other material. The acrylic resin, or other material, may be mixed with either or both ether and alcohol or other volatile solvents. For example, the coating material may be an acrylic resin mixed with volatile solvents, such as alcohol, butanol, ethaline, glycol, mono-butyl, and others. The ether and alcohol may allow the resin to be in liquid form before application. Contact  1910  may be placed in this bath at a high voltage, for example 20-100 volts. The voltage may attract resin ions to contact  1910  and the resin may form ED coating  2950  on contact  1910 . 
     After ED coating  2950  has been applied, the masking layer may be removed. For example, where the masking layer is wax, it may be removed using hot water. This may 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  may be formed of a precious-metal alloy. In this example, the contact area  2920  (and  2820  in  FIG. 28 ) may be formed of precious-metal alloy while other materials may be used to form beam  2910 , since beam is coated with ED coating  2950 . The use of resin or other coating  2950  may allow the use of a mix of materials. For example, a hard, precious-metal alloy or other material may be used for contact areas  2920  without the consequence of having a brittle beam  2910 . This may allow the beam  2910  to be formed of a more flexible, less brittle material. Moreover, the gradient coating techniques shown in  FIG. 25  above may be employed as well. 
     Where contacting area  2920  is formed of a precious-metal alloy, it may be desirable to save resources by reducing its size. This may require a more accurate application of the masking layer. Accordingly, in these and other embodiments of the present invention the masking layer may be formed by printing, such as with an ink jet, roller, pad, or other applicator. These and other embodiments of the present invention may provide contacts that are formed using 3-D printing. The precious-metal alloys used may 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, may be formed of various materials. For example, the beams and other contact portions may be formed of copper or other materials. The beams and other portions may be plated with various layers, such as those shown in  FIGS. 4, 9, 22, and 26 . 
     Contacts, such as contacts  1910 , may 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 may be formed. The contact and its carrier may 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 may be plated, for example using layers as shown in  FIGS. 4, 9, 22, and 26 . A masking layer may be applied to a contact area, such as contact area  2920 , in act  3020 . Other regions, such as surface mount contact portion  2930 , may be masked as well. This masking layer may be applied mechanically, by printing, such as with an ink jet, roller, pad, or other applicator, or by other method. The masking layer may be formed of wax, paraffin, or other material. 
     In act  3030 , an electrophoretic coating, such as ED coating  2950 , may 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 may 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 may be an acrylic resin, plastic, or other material. The acrylic resin, or other material, may be mixed with either or both ether and alcohol. For example, the coating material may be an acrylic resin mixed with volatile solvents, such as alcohol, butanol, ethaline, glycol, mono-butyl, and others. The ether and alcohol may allow the coating material to be in liquid form. The contact, such as contact  1910 , may be placed in this bath at a high voltage, for example 20-100 volts. The voltage may attract resin ions to contact, and the resin may form the ED coating  2950  on the contact. 
     After the ED coating has been applied in act  3030 , the masking layer may be removed in act  3040 . For example, where the masking layer is wax, it may be removed using hot water. This may also help to set the ED coating on the contact. The carrier may be removed in act  3050 . The contact, such as contact  1910 , may 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 may reduce the rate of corrosion by using various materials as a substrate for contacts in a connector. The substrate materials may be selected from materials which may provide dimensionally stable anodes in corrosive, applied voltage electrochemical operations. A catalytically active material, also stable in the corrosive application, may be coated on top of the substrate, for example by plating. That is, the present invention may use substrate materials that provide dimensionally stable anodes that are combined with contact coating materials to form a contact in a connector that may be stable even in the presence of high voltage and corrosive environments. 
     These dimensionally stable anode materials may have electrical resistances that may be higher than copper. This may normally make them poor candidates for electrical contacts. However, where dimensions of a contact substrate are small, the increase in absolute resistance may 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 may be used for a substrate. These materials may 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 may 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 may be used. Many of the selected materials form stable oxides which also may survive in highly corrosive environments. These may include titanium dioxide, ruthenium oxide, and palladium oxide. In these and other embodiments of the present invention, the contact coating materials may be used as substrate materials. When these materials are used, additional coatings may be used on the surface of the contact. 
     In a specific embodiment of the present invention, a contact used in a connector may be formed of a niobium substrate. The substrate may 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 may 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 may be used in other contexts. For example, they may 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 may 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 may be formed of copper or some combination of copper and a precious-metal alloy, or other materials, and may be plated with one or more of the various stacks shown herein. For example, contacts, such as contacts  220  may 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  may 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  may 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  may 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 may 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 may 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, may 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 may 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 may 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 may be included. For example, barrier layers, such as zinc barrier layers, may be used to protect magnets or other internal structures from corrosion by cladding or plating layers. Catalyst layers may be used to improve the rate of deposition for other layers, thereby improving the manufacturing process. These catalyst layers may be formed of palladium or other material. Stress separation layers, such as those formed of copper, may also be included in these and other embodiments of the present invention, including the above contacts. Other scratch protection, passivation, and corrosion resistance layers may also be included. 
     In various embodiments of the present invention, the components of contacts and their connector assemblies may be formed in various ways of various materials. For example, contacts and other conductive portions may be formed by stamping, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions may be formed of stainless steel, steel, copper, copper titanium, phosphor bronze, palladium, palladium silver, or other material or combination of materials. They may be plated or coated with nickel, gold, or other material. The nonconductive portions, such as the housings and other portions, may be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions may 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 may provide contacts and their connector assemblies that may be located in, and may 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 may 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 may 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: 20170320
Publication Date: 20190910
Grant Date: 20190910
Priority Date: 20160318
Inventors: WAGMAN, Daniel C.
KALLMAN, BENJAMIN J.
Esmaeili, Hani
KOWALSKI, STEFAN A.
MCDONALD, Daniel T.
JOL, ERIC S.
KWOK, RAYMUND W. M.
BARNSTEAD, MICHAEL W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R12/57", "inventive": true, "first": true, "tree": "[]"}, {"code": "C22C5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R24/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "C22C5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/115", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/09", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R24/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "C22C5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "C22C5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C9/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22C5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R24/60", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 59409883