Thermal barrier coating with a plasma spray top layer

Abstract

A turbine engine component has a substrate, a thermal barrier coating deposited onto the substrate, and a sealing layer of ceramic material on an outer surface of the thermal barrier coating for limiting molten sand penetration.

1 - 14 . (canceled) 
     
     
         15 . A method for forming a coating on a turbine engine component comprising the steps of:
 forming a thermal barrier coating on a surface of said turbine engine component; and   plasma spraying a sealing layer onto said thermal barrier coating.   
     
     
         16 . The method of  claim 15 , wherein said plasma spraying step comprises plasma spraying a ceramic material onto said thermal barrier coating. 
     
     
         17 . The method of  claim 15 , wherein said plasma spraying step comprises plasma spraying a yttria stabilized zirconia layer onto said thermal barrier coating. 
     
     
         18 . The method of  claim 15 , wherein said plasma spraying step comprises depositing said sealing layer using a plasma spray gun operating at from 30 to 70 volts and from 300 to 900 amps and a ceramic powder flow rate of from 30 to 70 grams per minute. 
     
     
         19 . The method of  claim 15 , wherein said thermal barrier coating step comprises depositing at least one layer of yttria stabilized zirconia onto said surface. 
     
     
         20 . The method of  claim 15 , wherein said thermal barrier coating step comprises depositing at least one layer of gadolinia stabilized zirconia onto said surface. 
     
     
         21 . The method of  claim 15 , wherein said thermal barrier coating step comprises depositing a ceramic material at a temperature of from 1700 to 2000° F., a pressure of from 0.05 to 2.0 millitors, and a feed rate of from 0.3 to 2.0 inches per hour. 
     
     
         22 . The method of  claim 15 , further comprising applying a bond coat to said surface of said turbine engine component prior to said thermal barrier coating forming step. 
     
     
         23 . The method according to  claim 22 , wherein said bond coat applying step comprises applying a material selected from the group of a MCrAlY coating, an aluminide coating, a platinum aluminide coating, a ceramic based material, and a silica based material. 
     
     
         24 - 33 . (canceled)