Low Thermal Conductivity, CMAS-Resistant Thermal Barrier Coatings

Abstract

A thermal barrier coating composition including a base oxide; a primary dopant including ytterbia; a first co-dopant including samaria; and a second co-dopant including at least one of lutetia, scandia, ceria, gadolinia, neodymia, or europia.

1 . A thermal barrier coating composition comprising:
 a base oxide;   a primary dopant comprising ytterbia;   a first co-dopant comprising samaria; and   a second co-dopant comprising at least one of lutetia, scandia, ceria, gadolinia, neodymia, or europia.   
   
   
       2 . The thermal barrier coating composition of  claim 1 , wherein the base oxide is selected from the group consisting of zirconia, hafnia, and combinations thereof. 
   
   
       3 . The thermal barrier coating composition of  claim 1 , wherein the primary dopant is present in a larger amount than either of the first co-dopant and the second co-dopant. 
   
   
       4 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises about 2 mol. % to about 40 mol. % of the primary dopant, about 0.1 mol. % to about 20 mol. % of the first co-dopant, about 0.1 mol. % to about 20 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       5 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises about 2 mol. % to about 20 mol. % of the primary dopant, about 0.5 mol. % to about 10 mol. % of the first co-dopant, about 0.5 mol. % to about 10 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       6 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises about 2 mol. % to about 10 mol. % of the primary dopant, about 0.5 mol. % to about 5 mol. % of the first co-dopant, about 0.5 mol. % to about 5 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       7 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises a cubic phase constitution. 
   
   
       8 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises a tetragonal t′ phase constitution. 
   
   
       9 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises a tetragonal t′ phase constitution and a cubic phase constitution. 
   
   
       10 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises RE 2 O 3 ZrO 2  compounds, RE 2 O 3 -HfO 2  compounds and combinations thereof. 
   
   
       11 . The thermal barrier coating composition of  claim 1 , wherein the thermal barrier coating comprises a mixture of a cubic phase constitution and a RE 2 O 3 -ZrO 2  compound, RE 2 O 3 -HfO 2  compounds and combinations thereof. 
   
   
       12 . The thermal barrier coating composition of  claim 1 , wherein the coating is essentially free of yttria. 
   
   
       13 . A thermal barrier coating composition comprising:
 a base oxide consisting essentially of zirconia, hafnia, or combinations thereof;   a primary dopant consisting essentially of ytterbia;   a first co-dopant consisting essentially of samaria; and   a second co-dopant selected from the group consisting of lutetia, scandia, ceria, gadolinia, neodymia, europia, and combinations thereof.   
   
   
       14 . The thermal barrier coating composition of  claim 13 , wherein the primary dopant is present in a larger amount than either of the first co-dopant and the second co-dopant. 
   
   
       15 . The thermal barrier coating composition of  claim 13 , wherein the coating consists of about 2 mol. % to about 40 mol. % of the primary dopant, about 0.1 mol. % to about 20 mol. % of the first co-dopant, about 0.1 mol. % to about 20 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       16 . The thermal barrier coating composition of  claim 13 , wherein the coating consists of about 2 mol. % to about 20 mol. % of the primary dopant, about 0.5 mol. % to about 10 mol. % of the first co-dopant, about 0.5 mol. % to about 10 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       17 . The thermal barrier coating composition of  claim 13 , wherein the coating consists of about 2 mol. % to about 10 mol. % of the primary dopant, about 0.5 mol. % to about 5 mol. % of the first co-dopant, about 0.5 mol. % to about 5 mol. % of the second co-dopant, and the balance base oxide and impurities. 
   
   
       18 . The thermal barrier coating composition of  claim 13 , wherein the thermal barrier coating comprises a cubic phase constitution. 
   
   
       19 . The thermal barrier coating composition of  claim 13 , wherein the thermal barrier coating comprises a tetragonal t′ phase constitution. 
   
   
       20 . The thermal barrier coating composition of  claim 13 , wherein the thermal barrier coating comprises a tetragonal t′ phase constitution and a cubic phase constitution. 
   
   
       21 . The thermal barrier coating composition of  claim 13 , wherein the thermal barrier coating comprises RE 2 O 3 —ZrO 2  compounds, RE 2 O 3 -HfO 2  compounds, and combinations thereof. 
   
   
       22 . The thermal barrier coating composition of  claim 13 , wherein the thermal barrier coating comprises a mixture of a cubic phase constitution and a RE 2 O 3 —ZrO 2  compound, RE 2 O 3 -HfO 2  compounds, and combinations thereof. 
   
   
       23 . The thermal barrier coating composition of  claim 13 , wherein the coating is essentially free of yttria. 
   
   
       24 . An article comprising:
 a thermal barrier coating applied to at least a portion of a substrate, wherein the thermal barrier coating comprises:
 a base oxide; 
 a primary dopant comprising ytterbia; 
 a first co-dopant comprising samaria; and 
 a second co-dopant comprising at least one of lutetia, scandia, ceria, gadolinia, neodymia, or europia. 
   
   
   
       25 . The article of  claim 24 , further comprising a bond coat applied to at least a portion of the substrate, wherein the thermal barrier coating is applied to the bond coat. 
   
   
       26 . The article of  claim 24 , further comprising an environmental barrier coating applied to at least a portion of the substrate, wherein the thermal barrier coating is applied to the environmental barrier coating. 
   
   
       27 . The article of  claim 24 , further comprising a bond coat applied to at least a portion of the substrate and an environmental barrier coating applied to the bond coat, wherein the thermal barrier coating is applied to the environmental barrier coating. 
   
   
       28 . The article of  claim 24 , wherein the thermal barrier coating consists essentially of:
 a base oxide selected from the group consisting of zirconia, hafnia, or combinations thereof;   a primary dopant consisting essentially of ytterbia;   a first co-dopant consisting essentially of samaria; and   a second co-dopant selected from the group consisting of lutetia, scandia, ceria, gadolinia, neodymia, europia, and combinations thereof.