Segmented abradable coatings and process (ES) for applying the same

Abstract

A segmented abradable ceramic coating comprises a bond coat layer, at least one segmented 7 weight percent yttria-stabilized zirconia layer disposed upon said bond coat layer, and at least one 12 weight percent yttria-stabilized zirconia layer disposed upon said at least one segmented 7 weight percent yttria-stabilized zirconia layer.

1 . A segmented abradable ceramic coating, comprising:
 a bond coat layer;   at least one segmented 7 weight percent yttria-stabilized zirconia layer disposed upon said bond coat layer; and   at least one 12 weight percent yttria-stabilized zirconia layer disposed upon said at least one segmented 7 weight percent yttria-stabilized zirconia layer.   
   
   
       2 . The coating of  claim 1 , wherein said at least one 12 weight percent yttria-stabilized zirconia layer is at least one segmented 12 weight percent yttria-stabilized zirconia layer. 
   
   
       3 . The coating of  claim 1 , further comprising a thermally grown oxide layer disposed between said bond coat layer and said at least one 7 weight percent yttria-stabilized zirconia layer. 
   
   
       4 . The coating of  claim 1 , wherein said at least one 7 weight percent yttria-stabilized zirconia layer has a thermal conductivity value of about 5 BTU in./hr. ft 2 ° F. to about 12 BTU in./hr. ft 2 ° F. 
   
   
       5 . The coating of  claim 1 , wherein said at least one 12 weight percent yttria-stabilized zirconia layer has a thermal conductivity value of about 3 BTU in./hr. ft 2 ° F. to about 10 BTU in./hr. ft 2 ° F. 
   
   
       6 . A coated article, comprising:
 a substrate having at least one surface;   a bond coat layer disposed upon said at least one surface;   at least one segmented 7 weight percent yttria-stabilized zirconia layer disposed upon said bond coat layer; and   at least one 12 weight percent yttria-stabilized zirconia layer disposed upon said at least one segmented 7 weight percent yttria-stabilized zirconia layer.   
   
   
       7 . The coated article of  claim 6 , wherein said at least one 12 weight percent yttria-stabilized zirconia layer is at least one segmented 12 weight percent yttria-stabilized zirconia layer. 
   
   
       8 . The coated article of  claim 6 , further comprising a thermally grown oxide layer disposed between said bond coat layer and said at least one 7 weight percent yttria-stabilized zirconia layer. 
   
   
       9 . The coated article of  claim 6 , wherein said at least one 7 weight percent yttria-stabilized zirconia layer has a thermal conductivity value of about 5 BTU in./hr. ft 2 ° F. to about 12 BTU in./hr. ft 2 ° F. 
   
   
       10 . The coated article of  claim 6 , wherein said at least one 12 weight percent yttria-stabilized zirconia layer has a thermal conductivity value of about 3 BTU in./hr. ft 2 ° F. to about 10 BTU in./hr. ft 2 ° F. 
   
   
       11 . The coated article of  claim 6 , wherein said at least one 7 weight percent yttria-stabilized zirconia layer has a thickness of about 1 mil (0.0254 mm) to about 60 mils (1.524 mm). 
   
   
       12 . The coated article of  claim 6 , wherein said at least one 12 weight percent yttria-stabilized zirconia layer has a thickness of about 1 mil (0.0254 mm) to about 60 mils (1.524 mm). 
   
   
       13 . A process for applying the segmented abradable ceramic coating of  claim 1  on an article, the process comprising:
 (1) depositing an amount of bond coat material sufficient to form said bond coat layer upon at least one surface of the article;   (2) depositing an amount of 7 weight percent yttria-stabilized zirconia sufficient to form a 7 weight percent yttria-stabilized zirconia layer upon said bond coat layer;   (3) heating said article to expand said 7 weight percent yttria-stabilized zirconia layer and promote vertical crack propagation therein to form said segmented 7 weight percent yttria-stabilized zirconia layer;   (4) depositing an amount of 12 weight percent yttria-stabilized zirconia sufficient to form said 12 weight percent yttria-stabilized zirconia layer upon said segmented 7 weight percent yttria-stabilized zirconia layer to form a coated article; and   (5) heating treating said coated article.   
   
   
       14 . The process of  claim 13 , prior to completing step (5) further comprising the step of heating said article to expand said 12 weight percent yttria-stabilized zirconia layer and promote vertical crack propagation therein to form a segmented 12 weight percent yttria-stabilized zirconia layer. 
   
   
       15 . The process of  claim 13 , wherein depositing said amount of bond coat material comprises thermal spraying said amount of bond coat material. 
   
   
       16 . The process of  claim 13 , wherein depositing said amount of 7 weight percent yttria-stabilized zirconia comprises thermal spraying said amount of 7 weight percent yttria-stabilized zirconia. 
   
   
       17 . The process of  claim 13 , wherein depositing said amount of 12 weight percent yttria-stabilized zirconia comprises thermal spraying said amount of 12 weight percent yttria-stabilized zirconia. 
   
   
       18 . The process of  claim 13 , wherein steps (2) and (3) are repeated at least one time. 
   
   
       19 . The process of  claim 13 , further comprising positioning a thermal spray apparatus about 3 inches to about 4 inches from said at least one surface. 
   
   
       20 . The process of  claim 13 , wherein heating further comprises backheating said at least one surface of said article. 
   
   
       21 . The process of  claim 13 , further comprising the step of forming a layer of thermally grown oxide upon said bond coat layer prior to performing step (2). 
   
   
       22 . The process of  claim 13 , further comprising the step of cooling said coated article after heat treating said coated article. 
   
   
       23 . The process of  claim 13 , wherein depositing an amount of 7 weight percent yttria-stabilized zirconia comprises depositing a 7 weight percent yttria-stabilized zirconia having a particle size of about 2 microns (0.002 mm) to about 175 microns (0.175 mm). 
   
   
       24 . The process of  claim 13 , wherein depositing an amount of 12 weight percent yttria-stabilized zirconia comprises depositing a 12 weight percent yttria-stabilized zirconia having a particle size of about 2 microns (0.002 mm) to about 175 microns (0.175 mm). 
   
   
       25 . The process of  claim 13 , wherein heat treating said coated article comprises forming a segmented 7 weight percent yttria-stabilized zirconia layer having a thickness of about 1 mil (0.0254 mm) to about 60 mils (1.524 mm) and a segmented 12 weight percent yttria-stabilized zirconia layer having a thickness of about 1 mil (0.0254 mm) to about 60 mils (1.524 mm).