Coating containing macroparticles and cathodic arc process of making the coating

Abstract

Provided is a method of cathodic arc process for making a coating containing macroparticles on an airfoil. A structure and/or composition of the macroparticles is selected to provide self-healing of the coating in a corrosive environment, and to provide corrosion resistance and erosion resistance to the coated airfoil.

1 . A method of forming a self-healing, corrosion and erosion resistant coating on an airfoil comprising:
 inserting an air foil into a cathodic arc apparatus;   vaporizing at least one metallic cathodic material by applying an arc to the metallic cathodic material to form atoms, ions and metallic macroparticles of the metallic cathodic material in an atmosphere within the apparatus so that the atoms form the coating on the airfoil; and   adjusting parameters of the arc to form liquid, semi-solid, or solid metallic macroparticles of the metallic cathodic material so that the metallic macroparticles embed into or onto the coating, wherein a structure and/or composition of the metallic macroparticles is selected to provide self-healing of the coating in a corrosive environment, and to provide corrosion resistance and erosion resistance to the coated airfoil.   
     
     
         2 . The method according to  claim 1 , wherein the atmosphere comprises nitrogen and the method further comprises forming the metallic macroparticles comprising a metal-nitride and the coating comprising a metal-nitride. 
     
     
         3 . The method according to  claim 1 , wherein the cathodic material is selected or the arc is applied to provide macroparticles having a spherical shape. 
     
     
         4 . The method according to  claim 2 , wherein the cathodic material and the macroparticles comprise titanium. 
     
     
         5 . The method according to  claim 1 , wherein the cathodic material is selected or the arc is applied in a manner to provide lenticular macroparticles. 
     
     
         6 . The method according to  claim 1 , wherein the cathodic material and the macroparticles comprise aluminum. 
     
     
         7 . The method according to  claim 1 , wherein the metallic macroparticles comprise aluminum and the corrosion resistance is enhanced by the formation of aluminum hydroxide in a corrosive environment so that the aluminum hydroxide blocks pores and crevices in the coating. 
     
     
         8 . The method according to  claim 1 , wherein the coating comprises multiple layers. 
     
     
         9 . The method according to  claim 1 , wherein the macroparticles comprise at least one of molybdenum disulphide, vanadium, or vanadium nitride. 
     
     
         10 . The method according to  claim 1 , wherein the macroparticles comprise at least 70 at % aluminum to provide the coating with a sacrificial component that is less noble than the work piece. 
     
     
         11 . The method according to  claim 1 , wherein the macroparticles comprise at least 90 at % aluminum to provide the coating with a sacrificial component that is less noble than the work piece. 
     
     
         12 . The method according to  claim 1 , wherein the cathodic material is deposited as a metal and/or in reactive gas to form a nitride, carbide, oxide or mixture thereof. 
     
     
         13 . The method according to  claim 1 , wherein the cathodic material comprises at least one selected from the group consisting of chromium, aluminum, titanium and other group IV, V and VI transition metals from the periodic table. 
     
     
         14 . The method according to  claim 1 , wherein the coating comprises multiple layers. 
     
     
         15 . A method of forming a self-healing, corrosion and erosion resistant coating on an airfoil comprising:
 inserting the airfoil into a cathodic arc apparatus;   vaporizing a first metallic cathodic material by applying an arc to the metallic cathodic material to form atoms, ions and metallic macroparticles of the first metallic cathodic material in an atmosphere within the apparatus so that the atoms form the coating on the airfoil; and   forming liquid, semi-solid, or solid macroparticles by applying a second arc to a second metallic cathodic material under conditions to form the macroparticles of the second metallic cathodic material so that the metallic macroparticles embed into or onto the coating, wherein a structure and/or composition of the macroparticles is selected to provide self-healing of the coating in a corrosive environment, and to provide corrosion resistance and erosion resistance to the coated airfoil.   
     
     
         16 . The method according to  claim 15 , wherein the atmosphere comprises nitrogen and the method further comprises forming the metallic macroparticles comprising a metal-nitride and the coating comprising a metal-nitride. 
     
     
         17 . The method according to  claim 15 , wherein the second cathodic material is selected or the second arc is applied to provide macroparticles having a spherical shape. 
     
     
         18 . The method according to  claim 15 , wherein the second cathodic material and the macroparticles comprise titanium. 
     
     
         19 . The method according to  claim 15 , wherein the second cathodic material is selected or the second arc is applied in a manner to provide lenticular macroparticles. 
     
     
         20 . The method according to  claim 15 , wherein the second cathodic material and the macroparticles comprise aluminum or aluminum alloy. 
     
     
         21 . The method according to  claim 15 , wherein the macroparticles comprise at least 70 at % aluminum to provide the coating with a sacrificial component that is less noble than the workpiece. 
     
     
         22 . The method according to  claim 15 , wherein the macroparticles comprise at least 90 at % aluminum to provide the coating with a sacrificial component that is less noble than the workpiece. 
     
     
         23 . The method according to  claim 15 , wherein the cathodic material is deposited as a metal and/or in reactive gas to form a nitride, carbide, oxide or mixture thereof. 
     
     
         24 . The method according to  claim 15 , wherein the cathodic material comprises at least one selected from the group consisting of chromium, aluminum, titanium and other group IV, V and VI transition metals from the periodic table. 
     
     
         25 . The method according to  claim 15 , wherein the metallic macroparticles comprise aluminum and the corrosion resistance is enhanced by the formation of aluminum hydroxide in a corrosive environment so that the aluminum hydroxide blocks pores and crevices in the coating. 
     
     
         26 . An airfoil having a surface and a self-healing, corrosion and erosion resistant coating on the surface formed by the method of  claim 1 , wherein the structure and/or composition of the macroparticles provides the self-healing, corrosion and erosion resistance to the coating.