Method for applying a NiA1 based coating by an electroplating technique

Abstract

The present invention provides a coated article made using a plating process, either electroless or electrolytic, whereby nickel is plated on the article using a solution that includes a suspension of powders or containing one or more of the following elements: Ni, Cr, Al, Zr, Hf, Ti, Ta, Si, Ca, Fe, Y and Ga. Optionally, the coating is then heat treated at a temperature above about 1600.degree. F. for an effective amount of time to allow to homogenize the coating by allowing effective interdiffusion between the species. The level of aluminum may be altered to produce a coating of the predominantly beta phase of the NiAl alloy composition. Optionally, a TBC layer is applied over the predominantly beta phase NiAl alloy composition metallic bond coat.

1 - 13 . (canceled) 
   
   
       14 . An article for use in a gas turbine that includes at least one airfoil comprising:
 a superalloy substrate, wherein the superalloy is selected from the group of nickel base superalloys, cobalt base superalloys, iron base superalloys and combinations thereof; and   a composite coating electrodeposited over the superalloy substrate the composite coating further comprising a metal matrix wherein the metal matrix includes nickel and further includes particles selected from the group consisting of Ni, Cr, Al, Zr, Hf, Ti, Ta, Si, Ca, Fe, Y, Ga, and combinations thereof, and wherein upon deposition of the composite coating on the superalloy substrate, the particles form a second phase dispersed in the metal matrix which forms a first phase; and aluminum, wherein the aluminum is deposited over the metal matrix by an aluminiding process in sufficient amount to provide a NiAl stoichiometry to the metal matrix and embedded particles thereby forming a substantially β phase of NiAl having additional alloying elements; and, optionally,   an thermal barrier coating deposited over the composite coating.   
   
   
       15 - 17 . (canceled) 
   
   
       18 . The article of  claim 14 , wherein the composite coating is substantially homogeneous, the elements in the particles being interdiffused throughout the metal matrix including nickel. 
   
   
       19 . The article of  claim 14 , wherein the composite coating comprises: about 30 to 60 atomic percent Al; at least one element selected from the group consisting of Cr in the amount of about 0.5 to about 25 atomic percent, Ti in the amount of about 0.1 to about 5 atomic percent, and Hf in the amount of about 0.01 to about 2 atomic percent; optionally at least one element selected from the group consisting of Ta in the amount of about 0.1 to about 5 atomic percent, Si in the amount of about 0.1 to about 5 atomic percent, Ga in the amount of about 0.02 to about 0.2 atomic percent, Zr in the amount of about 0.01 to about 0.5 atomic percent, Ca in the amount of about 0.01 to about 1 atomic percent, Fe in the amount of about 0.02 to about 0.5 atomic percent, Y in the amount of about 0.01 to about 1 atomic percent; and the balance nickel and incidental impurities. 
   
   
       20 . The article of  claim 19 , wherein the composite coating is substantially homogeneous, the elements in the powders being interdiffused throughout the metal matrix including nickel. 
   
   
       21 . The article of  claim 14  wherein the composite coating comprises: about 30 to about 50 atomic percent Al; about 0.5 to about 15 atomic percent Cr; at least one element selected from the group consisting of Ti in the amount of about 0.1 to about 5 atomic percent, Hf in the amount of about 0.01 to about 2 atomic percent, Si in the amount of about 0.1 to about 2 atomic percent, Ga in the amount of about 0.02 to about 0.2 atomic percent, Zr in the amount of about 0.01 to about 0.5 atomic percent, Fe in the amount of about 0.02 to about 0.5 atomic percent, Y in the amount of about 0.01 to about 1 atomic percent; and the balance nickel and incidental impurities. 
   
   
       22 . The article of  claim 21 , wherein the composite coating is substantially homogeneous, the elements in the particles being interdiffused throughout the metal matrix including nickel. 
   
   
       23 . The article of  claim 14 , wherein the particle size of the particles is less than about 25 microns. 
   
   
       24 . The article of  claim 14 , wherein the particle size of the particles is less than about 15 microns. 
   
   
       25 - 35 . (canceled)