Abstract:
The invention relates to a method and an apparatus for applying metallic, ceramic or composite thin film coatings onto parts, components and tools (e.g. gas turbine engine compressor blades or cutting tools) by a cathodic arc deposition technique. The method and the apparatus allows for a continually changing structure of the applied film by nanoimplanting atoms, molecules, compounds or other chemical species and structures of different materials thus coating a substrate during a single process. Furthermore, during the same process it allows for creating a coating with specific parameters as required. For instance: hardness, smoothness, corrosion resistance, erosion resistance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Provisional Patent Application No. 61/514,445, filed on Aug. 2, 2011. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an arc source for a cathodic arc physical vapor deposition system. The cathodic arc vacuum evaporation technique is used to deposit metallic, ceramic and composite coatings on the following; cutting tools, punching and forming tools and injection molding tools. It is further applied in optical and decorative applications, medical tools and implants, automotive and aerospace industries. It&#39;s becoming widely used in aircraft, generators and tank gas turbines. 
     Each of these applications requires different coating properties. Parameters like: yield strength, toughness, hardness, adhesion, surface roughness, wear resistance, corrosion resistance and erosion resistance have to be specifically chosen, the coating is then designed based on those requirements. 
     For example helicopter turbine engine compressor blades used in harsh desert conditions require erosion resistance. Gas turbine engines ingest sand and dust which erode the leading edges of the airfoils. Large particles roll over the blades&#39; frontal surface. Engine power begins to deteriorate rapidly leading to early blade replacement and decreased fuel economy. Engine operating life is reduced. 
     Modern surface engineering requires nanotechnology adjustments to create the state of the art thin films. Instruments of surface engineering have to be more and more sophisticated to generate nanostructure, nanocomposite, single or multi layers and super lattices. 
     There is a couple existing patents which provide methods of modifying physical vapor deposition coating.
     U.S. Pat. No. 3,900,592 presents a method for coating where the composition of the deposit is changed by introducing a gas during the deposition to produce a hardness gradient in the deposit.   U.S. Pat. No. 4,839,245 describes zirconium nitride coating for turbine blades to provide erosion resistance.   U.S. Pat. No. 5,185,211 presents nonstoichiometric titanium nitride coating.   U.S. Pat. No. 5,242,753 discloses substoichiometric zirconium nitride coating.   U.S. Pat. No. 6,797,335 provides method of deposition of erosion and corrosion resistant coatings on machine components.   U.S. Pat. No. 7,186,092 presents a coated turbine airfoil having an improved impact and erosion resistance.   U.S. Pat. No. 7,211,338 provides hard, ductile coating system.   U.S. Pat. No. 7,229,675 discloses a method of forming a multilayer coating by combining and simultaneously or consecutively using of various technologies.   U.S. Pat. No. 7,744,986 presents multilayered resistant coating for gas turbines.   

     These methods are using several known arc evaporation sources.
     U.S. Pat. No. 3,625,848 describes a beam gun for use in creating an arc discharge between an anode and a cathode.   U.S. Pat. No. 4,492,845 provides an arc evaporation apparatus having an annular cathode.   U.S. Pat. No. 4,563,262 provides a cathode with unitary design, consisting of a plurality of layers of different metals.   U.S. Pat. No. 4,622,452 presents an electrode apparatus with a coolant cavity for actively and efficiently cooling substantially the entire lower surface of the electrode.   U.S. Pat. No. 5,203,980 provides a large surface cathode arrangement with a consumable cathode plate that is connected via an intermediate plate with high electrical and thermal conductivity to a base plate.   U.S. Pat. No. 5,317,235 discloses a cathodic arc metal deposition apparatus that prevents the deposition of metal droplets with the metal ions being deposited.   

     Many methods of efficient utilization were provided.
     U.S. Pat. No. 3,783,231 shows a cathode using a magnetic field for retaining the cathode spot on the surface of the cathode.   U.S. Pat. No. 3,793,179 presents an apparatus which is maintaining the cathode spot using a shield.   U.S. Pat. No. 4,452,686 provides a cathode, a cylindrical anode and a focusing solenoid arranged coaxially with the cathode.   U.S. Pat. No. 4,512,867 discloses an apparatus which performs more efficient utilization of the electrode using a magnetic field to spread plasma over the evaporative surface.   U.S. Pat. No. 4,551,221 describes an apparatus having a solenoid coaxially disposed relative to the consumable cathode and having a tubular anode.   U.S. Pat. No. 4,673,477 discloses an apparatus in which the track of the arc is controlled with a magnetic field established with the permanent magnet that is moved in a closed path relative to the cathode.   U.S. Pat. No. 5,269,896 discloses a cathodic arc in which random motion of an arc spot is extinguished by a shield surrounding a circumferential side of the cathode with a gap.   U.S. Pat. No. 5,298,136 describes an apparatus which is controlling and steering the arc in a desired path as necessary to produce coatings of the desired compositions using magnetic fields generated to provide arc path control and modulation for efficient cathode utilization.   U.S. Pat. No. 5,380,421 presents an apparatus for the production of coatings, including a rectangular cathode plate, primary and auxiliary anodes and static and dynamic magnetic stabilizing subsystems.   U.S. Pat. No. 5,458,754 provides a plasma enhancement apparatus includes a magnet disposed about a magnet axis and defining an aperture for plasma.   U.S. Pat. No. 5,861,088 discloses a magnetic field cathode for arc discharge vaporizers.   U.S. Pat. No. 5,895,559 presents a cathodic arc which is maintaining the cathode spot using an insulating ring.   U.S. Pat. No. 5,972,185 shows a cathodic arc which produces a magnetic field for steering the arc around an evaporative surface.   U.S. Pat. No. 6,009,829 provides an apparatus for driving the arc around an axially extending evaporative surface of the cathode.   U.S. Pat. No. 6,103,074 discloses an apparatus which is creating a magnetic field of a distinctive cusp shape to trap and focus plasma particles.   U.S. Pat. No. 6,334,405 presents an evaporation source with a magnetic field generating source which can reduce the number of molten particles arriving at a substrate and deviation of occurrence of arc spots can be suppressed.   U.S. Pat. Nos. 6,645,354 and 6,929,727 provide an arc coating apparatus having a steering magnetic field source comprising steering conductors.   U.S. Pat. No. 6,692,623 discloses an arc deposition apparatus includes a plurality of magnetic coils for guiding plasma.   U.S. Pat. No. 6,869,509 presents an arc source which comprises an insulated counter-electrode and/or an AC magnet system.   U.S. Pat. No. 6,936,145 describes a cathodic arc with external current switching contacts to improve coating uniformity.   U.S. Pat. No. 7,828,946 discloses a magnetic guide that controls an electric arc between an anode and a cathode.   

     What is needed is an apparatus which can combine all known surface engineering techniques in the cathodic arc physical vapor deposition technology and generate high quality coatings with a relatively simple and economical method of production. 
     BRIEF SUMMARY OF THE INVENTION 
     It is the objective of this invention to provide a method and an apparatus which allows for continually changing the structure of the applied film by nanoimplanting atoms, molecules, compounds or other chemical species and structures of different materials thus coating a substrate during one cathodic arc physical vapor deposition process, all while creating a coating with the required parameters. 
     The present invention offers a device and a method that would be simpler in design and operation than its predecessors. It allows for more possible options and combinations of surface engineering. 
     The apparatus implements a cathode with special sections of diverse materials to provide the required multiple selections. 
     The disclosed solution presents special zones of a constant magnetic field, created by magnetic coils or magnets, which maintain a cathode spot in the required section of the cathode containing the material of choice. 
     The specified method, as a result of various combinations of materials allows for controlling the hardness gradient, which is increased or decreased as required. 
     This method as a result of multiple material selections allows for managing stoichiometry. This has great influence on the hardness of the coating. 
     The present method as a result of available combinations of materials allows for creating multi nanocomposites. 
     The method allows for creating multi material nanostructures. The apparatus is able to build multi layers and super lattices with unusual combinations and choices of options. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention will be thoroughly described by referencing the accompanying drawings, wherein: 
         FIG. 1  is a sectional view of an apparatus for a cathodic arc deposition, made according to the present invention with particular reference to the arc source with an electronic material sequencer. 
         FIG. 2  is a sectional view of an apparatus for a cathodic arc deposition, made according to the present invention with particular reference to the arc source with a mechanical material sequencer. 
         FIG. 3  is a sectional view of the arc source with a round cathode including six material sections and six sextant shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 4  is a sectional view of the arc source with a round cathode including six material sections and six circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 5  is a sectional view of the arc source with a round cathode including six material sections and multiple circle shaped magnetic coils of varying size powered by an electronic material sequencer. 
         FIG. 6  is a sectional view of the arc source with a round cathode including six material sections and a sextant shaped magnet motorized by a mechanical material sequencer. 
         FIG. 7  is a sectional view of the arc source with a round cathode including six material sections and a rectangle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 8  is a sectional view of the arc source with a round cathode including six material sections and multiple circle shaped magnets of varying size motorized by a mechanical material sequencer. 
         FIG. 9  is a sectional view of the arc source with a round cathode including two sections of concentric circle shaped materials and multiple circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 10  is a sectional view of the arc source with a round cathode including two sections of concentric circle shaped materials and multiple circle shaped magnetic coils in two levels powered by an electronic material sequencer. 
         FIG. 11  is a sectional view of the arc source with a round cathode including two sections of concentric circle shaped materials and multiple circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 12  is a sectional view of the arc source with a round cathode including three sections of concentric circle shaped materials and multiple circle shaped magnetic coil powered by an electronic material sequencer. 
         FIG. 13  is a view of a round cathode including two material sections and two half circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 14  is a view of a round cathode including two material sections and a half circle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 15  is a view of a round cathode including two material sections and multiple circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 16  is a view of a round cathode including two material sections and multiple circle shaped magnets motorized by a mechanical material sequencer. 
         FIG. 17  is a view of a round cathode including three material sections and three one third circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 18  is a view of a round cathode including three material sections and a third circle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 19  is a view of a round cathode including three material sections and three circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 20  is a view of a round cathode including three material sections and a circle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 21  is a view of a round cathode including four material sections and four quarter circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 22  is a view of a round cathode including four material sections and a quarter circle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 23  is a view of a round cathode including four material sections and four circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 24  is a view of a round cathode including four material sections and a circle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 25  is a view of a round cathode including five material sections. 
         FIG. 26  is a view of a round cathode including eight material sections. 
         FIG. 27  is a view of a hexagonal cathode including six material sections. 
         FIG. 28  is a view of a triangle cathode including four material sections. 
         FIG. 29  is a view of a square cathode including two material sections. 
         FIG. 30  is a view of a square cathode with four material sections. 
         FIG. 31  is a view of a rectangle cathode with six material sections and six rectangle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 32  is a view of a rectangle cathode with six material sections and a rectangle shaped magnet motorized by a mechanical material sequencer. 
         FIG. 33  is a view of a rectangle cathode with eighteen material sections and eighteen square shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 34  is a view of a rectangle cathode with eighteen material sections and a square shaped magnet motorized by a mechanical material sequencer. 
         FIG. 35  is a view of a rectangle cathode with eighteen material sections and eighteen circle shaped magnetic coils powered by an electronic material sequencer. 
         FIG. 36  is a view of a rectangle cathode with eighteen material sections and a circle shaped magnet motorized by a mechanical material sequencer. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention employs an apparatus which within one process provides a continuously changing structure of the applied film. 
       FIG. 1  presents a cathodic arc physical vapor deposition system which contains: a vacuum processing chamber  1 , an arc source  4  with an Arc Power Supply (APS)  50 , a chamber evacuation system, a gas supply system, a substrate holding device, a bias voltage supply and a process control system. 
     The arc source  4  is assembled to an anode  5 , insulated from the anode  5  by an insulator  31  and sealed from vacuum by o-rings  41 . The anode  5  is fixed to a chamber flange  2 . The anode  5  is insulated from the chamber  1  by an insulator  3 . The arc source  4  contains a flange  15  which through an insulator  30  is supporting a cathode holder  11 . A cathode  10  is held by the cathode holder  11  and locked by a holding ring  12 . The cathode holder  11  is isolated from the vacuum by o-rings  42  and  43 . The cathode  10  is shielded by a cover  13 . The cathode holder  11  and the cathode  10  are water cooled. The cooling is provided by a water distribution insert,  14  which is fixed by a nut  16  and sealed from a water leak by o-rings  44 ,  45  and  46 . Water is delivered through a water input connector  20  distributed by a water collector  17  and drained by a water connector  21 . The water collector  17  is fixed by a nut  18 . Internal constant magnetic field coils  61  and  62 , controlled by an electronic material sequencer  60  are placed directly behind the cathode  10 . The arc power supply  50  is connected to the arc source  4  through a connector  51  and to an arc starter  52 . 
     During the process, when the vacuum system establishes the selected parameters of the process the arc source  4  is then powered by the arc power supply  50  and started by the arc starter  52 . At the same time one of the internal constant magnetic field coils  61  or  62  is selected and powered by the electronic material sequencer  60 . The magnetic field created by the coil is maintaining the cathode spot within the borders of required zone. The borders of the internal constant magnetic field correspond to the borders of section of selected material. Magnetic lines of force are normal (perpendicular) to the surface of the cathode  10 . During the process the electronic material sequencer  60  is changing the material as per programmed sequence. 
       FIG. 2  shows a cathodic arc physical vapor deposition system in the same configuration as in  FIG. 1  with one exception; internal constant magnetic field coils  61  and  62  are replaced by a magnet  72 . The magnet  72  is controlled by a step motor  71  and a mechanical material sequencer  70 . 
     During the process, when the vacuum system establishes the selected parameters of the process the arc source  4  is powered by the arc power supply  50  and started by the arc starter  52 . At the same time the magnet  72  is motorized by the mechanical material sequencer  70  and is set in the required position. The magnetic field created by the magnet is maintaining the cathode spot inside the borders of the required zone. Magnetic lines of force are normal (perpendicular) to the surface of the cathode  10 . The borders of the internal constant magnetic field zone correspond to the borders of the section of selected material. During the process the mechanical material sequencer  70  is changing material as per programmed sequence. 
     Different shapes of the cathode with diverse material sections, and varying magnetic coils and magnets are shown in the next drawings. 
     The arc source  4  with a round cathode  10  including six sections of materials  81 ,  82 ,  83  etc. is introduced in  FIG. 3 . There are six sextant shaped magnetic coils  61 ,  62  etc. assembled in the insert  14 . The sextant shaped magnetic coil corresponds to the specific section of the cathode containing a particular material. 
       FIG. 4  is another option of the same solution. Six circle shaped magnetic coils  61 ,  62  etc. are used instead of sextant shaped magnetic coils. This option does not provide complete and equal utilization of the materials ( 81 ,  82 ,  83  etc) as opposed to the previous option. 
     An alternative with better utilization is presented in  FIG. 5 . Multiple circle shaped magnetic coils  61 ,  62  etc. of varying size fill the sextant shaped zones which correspond to the specific section of the cathode containing one of the particular materials  81 ,  82 ,  83  etc. All the magnetic coils of varying size should have an equal magnetic field. 
       FIG. 6  implements a version with a sextant shaped magnet  72  for the arc source with a round cathode including six material sections  81 ,  82 ,  83  etc. 
     The sextant shaped magnet can be replaced by a rectangle shaped magnet  72  like in  FIG. 7 . In this option complete and equal utilization of materials  81 ,  82 ,  83  is an issue. 
     A better alternative for earlier adaptation is  FIG. 8  with multiple circle shaped magnets  72  of varying size. The magnets fill the sextant shaped zone corresponding to the specific section of the cathode containing one of the particular materials  81 ,  82 ,  83  etc. All the magnets of varying size should have an equal magnetic field. 
       FIG. 9  presents the arc source  4  with a round cathode including two sections of concentric circle shaped materials  81 ,  82  and multiple circle shaped magnetic coils  61 ,  62 . The two concentric circles compose an inner circle  81  and an outer ring  82 . 
     An option with two sections of concentric circle shaped materials  81 ,  82  and multiple circle shaped magnetic coils  61 ,  62  distributed on two levels is shown in  FIG. 10 . This solution provides complete and equal utilization of the material. 
     A version providing a similar advantage is presented in  FIG. 11  with two sections of concentric circle shaped materials  81 ,  82  and multiple circle shaped magnetic coils  61 ,  62 . 
       FIG. 12  shows further possible potential of the device, the arc source with a round cathode including three sections of concentric circle shaped materials  81 ,  82 ,  83  and multiple circle shaped magnetic coils  61 ,  62 ,  63 . The three concentric circles compose an inner circle  81 , a middle ring  82  and an outer ring  83 . The concentric circle shaped magnetic coils  61 ,  62 ,  63  correspond to the specific section of the cathode containing one of the particular materials  81 ,  82 ,  83 . 
     In  FIG. 13  a version with a round cathode including two material sections  81 ,  82  and two half circle shaped magnetic coils  61 ,  62  is presented. 
     The same half circle shaped idea is implemented in  FIG. 7   b . This time around the cathode includes two material sections  81 ,  82  and is controlled by a half circle shaped magnet  72 . 
       FIG. 15  and  FIG. 16  are simpler solutions of the idea described earlier; a round cathode including two material sections  81 ,  82  and multiple circle shaped magnetic coils  61 ,  62  or multiple circle shaped magnets  72 . Once again complete and equal utilization of materials  81 ,  82  is an issue. 
     Furthermore the following are additional developments of the options presented before:  FIG. 17  with a round cathode including three material sections  81 ,  82 ,  83  and three third circle shaped magnetic coils  61 ,  62 ,  63 ;  FIG. 18  with a round cathode including three material sections  81 ,  82 ,  83  and a third circle shaped magnet  72 ;  FIG. 19  with a round cathode including three material sections  81 ,  82 ,  83  and three circle shaped magnetic coils  61 ,  62 ,  63 ;  FIG. 20  with a round cathode including three material sections  81 ,  82 ,  83  and a circle shaped magnet  72 ;  FIG. 11   a  with a round cathode including four material sections  81 ,  82 ,  83 ,  84  and four quarter circle shaped magnetic coils  61 ,  62 ,  63 ,  64 ;  FIG. 22  with a round cathode including four material sections  81 ,  82 ,  83 , and a quarter circle shaped magnet  72 ;  FIG. 23  with a round cathode including four material sections  81 ,  82 ,  83 ,  84  and four circle shaped magnetic coils  61 ,  62 ,  63 ,  64 ; and  FIG. 24  with a round cathode including four material sections  81 ,  82 ,  83 ,  84  and a circle shaped magnet  72 . 
       FIG. 25  with a round cathode includes five material sections  81 ,  82 ,  83 ,  84 ,  85  and  FIG. 26  a round cathode includes eight material sections  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87 ,  88  which show possible combinations of dividing the round cathode into the necessary quantity of material segments to reach the requested plurality of materials. 
     Different shapes of the cathode are shown in the following:  FIG. 27  with a hexagonal cathode including six material sections  81 ,  82 ,  83 ,  84 ,  85 ,  86 ;  FIG. 28  with a triangle cathode including four material sections  81 ,  82 ,  83 ,  84 ;  FIG. 29  with a square cathode including two material sections  81 ,  82 ; and  FIG. 30  with a square cathode with four material sections  81 ,  82 ,  83 ,  84 . 
       FIG. 31  presents a rectangle cathode with six material sections  81 ,  82 ,  83 ,  84 ,  85 ,  86  and six rectangle shaped magnetic coils  61 ,  62 ,  63 ,  64 ,  65 ,  66 . This type of configuration is very useful for large area arc sources. 
     Continuation of this idea is  FIG. 32  witch shows a rectangular cathode with six material sections  81 ,  82 ,  83 ,  84 ,  85 ,  86  and a rectangle shaped magnet  72 . The magnet  72  is mechanically moved using a step motor or pneumatic or hydraulic device controlled by the mechanical material sequencer. 
     Another example of a rectangular cathode is  FIG. 33  with eighteen material sections  81  etc. and eighteen square shaped magnetic coils  61  etc. 
     A motorized square shaped magnet  72  with eighteen material sections  82  etc. is presented in  FIG. 34 . 
       FIG. 35  with a rectangular cathode containing eighteen material sections  81  etc and eighteen circle shaped magnetic coils  61  etc. implements a less efficient version in terms of equal utilization than the version presented in  FIG. 33 . 
     In  FIG. 36  a rectangular cathode with eighteen sections of materials  82  etc. and a circle shaped magnet  72  is shown. 
     This type of magnetic field, formed by the mentioned internal constant magnetic field coils or magnets, allows implement many combinations of the magnetic field zone shapes. This permits arbitrary modeling of the cathode shape and material section shape of the particular cathode. 
     Although the present invention has been described with reference to preferred embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.