Turbine component other than airfoil having ceramic corrosion resistant coating and methods for making same

Abstract

An article comprising a turbine component other than an airfoil having a metal substrate and a ceramic corrosion resistant coating overlaying the metal substrate. This coating has a thickness up to about 5 mils (127 microns) and comprises a ceramic metal oxide selected from the group consisting of zirconia, hafnia and mixtures thereof. This coating can be formed by a method comprising the following steps: (a) providing a turbine component other than an airfoil comprising the metal substrate; (b) providing a gel-forming solution comprising a ceramic metal oxide precursor; (c) heating the gel-forming solution to a first preselected temperature for a first preselected time to form a gel; (d) depositing the gel on the metal substrate; and (e) firing the gel at a second preselected temperature above the first preselected temperature to form the ceramic corrosion resistant coating comprising the ceramic metal oxide. This coating can also be formed by alternative methods wherein a ceramic composition comprising the ceramic metal oxide is deposited by physical vapor deposition on the metal substrate to provide a strain-tolerant columnar structure, or is thermal sprayed on the metal substrate.

1 . A method comprising the following steps:
 (a) providing a turbine component comprising a metal substrate; and   (b) depositing a ceramic composition comprising a ceramic metal oxide on the metal substrate by physical vapor deposition to form a ceramic corrosion resistant coating comprising the ceramic metal oxide and having a strain-tolerant columnar structure, wherein the ceramic metal oxide is selected from the group consisting of zirconia, hafnia and mixtures thereof.   
   
   
       2 . The method of  claim 1  wherein step (b) is carried out by electron beam physical vapor deposition of the ceramic composition on the metal substrate. 
   
   
       3 . The method of  claim 1  wherein the turbine component provided during step (a) is a compressor or turbine disk. 
   
   
       4 . The method of  claim 1  wherein the turbine component provided during step (a) is a seal element. 
   
   
       5 . A method comprising the following steps:
 (a) providing a turbine component other than a turbine airfoil comprising a metal substrate; and   (b) thermal spraying a ceramic composition comprising a ceramic metal oxide on the metal substrate to form a ceramic corrosion resistant coating comprising the ceramic metal oxide, wherein the ceramic metal oxide is selected from the group consisting of zirconia, hafnia and mixtures thereof.   
   
   
       6 . The method of  claim 5  wherein step (b) is carried out by plasma spraying the ceramic composition on the metal substrate. 
   
   
       7 . The method of  claim 5  wherein the turbine component provided during step (a) is a compressor or turbine disk. 
   
   
       8 . The method of  claim 5  wherein the turbine component provided during step (a) is a seal element.