CMAS-Resistant Thermal Barrier Coatings

Abstract

A coating including a CMAS-resistant layer with a rare earth oxide. The CMAS-resistant layer is essentially free of zirconia and hafnia, and may further include at least one of alumina, silica, and combinations thereof.

1 - 44 . (canceled) 
     
     
         45 . A coating comprising a CMAS-resistant layer comprising a rare earth oxide and alumina, wherein the CMAS-resistant layer is essentially free of zirconia and hafnia. 
     
     
         46 . The coating of  claim 45 , wherein the CMAS-resistant layer further comprises silica. 
     
     
         47 . The coating of  claim 46 , wherein the CMAS-resistant layer comprises 1 mol. % to 100 mol. % of at least one rare earth oxide and up to 99 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         48 . The coating of  claim 47 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         49 . The coating of  claim 46 , wherein the CMAS-resistant layer comprises 10 mol. % to 90 mol. % of at least one rare earth oxide, and 10 mol. % to 90 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         50 . The coating of  claim 49 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         51 . The coating of  claim 46 , wherein the CMAS-resistant layer comprises 20 mol. % to 80 mol. % of at least one rare earth oxide and 20 mol. % to 80 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         52 . The coating of  claim 51 , wherein the CMAS-resistant layer further comprises 1 mol. % to 30 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         53 . The coating of  claim 45 , wherein the rare earth oxide is selected from the group consisting of oxides of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and combinations thereof. 
     
     
         54 . The coating of  claim 45 , wherein the CMAS-resistant layer is about 0.1 mil to about 60 mil thick. 
     
     
         55 . The coating of  claim 45 , wherein the CMAS-resistant layer is about 0.5 mil to about 15 mil thick. 
     
     
         56 . The coating of  claim 45 , wherein the coating further comprises a second layer comprising at least one of: a MCrAlY alloy, wherein M is selected from Ni, Co, and NiCo; a β-NiAl alloy; a γ-Ni+γ′-Ni 3 Al alloy; rare earth oxide-stabilized zirconia, rare earth oxide-stabilized hafnia, mullite, silicon, barium strontium aluminosilicate, calcium aluminosilicate, cordierite, lithium aluminosilicate, rare earth silicates, and combinations thereof, wherein the CMAS-resistant layer is adjacent the second layer. 
     
     
         57 . The coating of  claim 56 , wherein the β-NiAl alloy further comprises at least one of Pt, Cr, Hf, Zr, Y, Si, and combinations thereof. 
     
     
         58 . The coating of  claim 56 , wherein the γ-Ni+γ′-Ni 3 Al alloy further comprises at least one of Pt, Cr, Hf, Zr, Y, Si, and combinations thereof. 
     
     
         59 . The coating of  claim 56 , further comprising a transitional layer, wherein the transitional layer is adjacent the second layer and wherein the CMAS-resistant layer is adjacent the transitional layer. 
     
     
         60 . A coating comprising:
 a CMAS-resistant layer comprising a rare earth oxide; and   an environmental barrier coating (EBC), wherein the CMAS-resistant layer is adjacent the EBC.   
     
     
         61 . The coating of  claim 60 , wherein the CMAS-resistant layer further comprises at least one of alumina, silica, and combinations thereof. 
     
     
         62 . The coating of  claim 60 , wherein the rare earth oxide is selected from scandia, yttria, lanthana, ceria, praseodymia, neodymia, promethia, samaria, europia, gadolinia, terbia, dysprosia, holmia, erbia, thulia, ytterbia, lutetia, and combinations thereof. 
     
     
         63 . The coating of  claim 60 , wherein the CMAS-resistant layer is about 0.1 mil to about 60 mil thick. 
     
     
         64 . The coating of  claim 60 , further comprising a transitional layer, wherein the transitional layer is adjacent the EBC and wherein the CMAS-resistant layer is adjacent the transitional layer. 
     
     
         65 . The coating of  claim 61 , wherein the CMAS-resistant layer comprises 1 mol. % to 100 mol. % of at least one rare earth oxide and up to 99 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         66 . The coating of  claim 65 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         67 . The coating of  claim 61 , wherein the CMAS-resistant layer comprises 10 mol. % to 90 mol. % of at least one rare earth oxide, and 10 mol. % to 90 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         68 . The coating of  claim 67 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         69 . The coating of  claim 61 , wherein the CMAS-resistant layer comprises 20 mol. % to 80 mol. % of at least one rare earth oxide and 20 mol. % to 80 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         70 . The coating of  claim 69 , wherein the CMAS-resistant layer further comprises 1 mol. % to 30 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         71 . An article comprising:
 a substrate; and   a CMAS-resistant layer comprising a rare earth oxide and alumina, wherein the CMAS-resistant layer is essentially free of zirconia and hafnia.   
     
     
         72 . The article of  claim 71 , wherein the CMAS-resistant layer further comprises silica. 
     
     
         73 . The article of  claim 72 , wherein the CMAS-resistant layer comprises 1 mol. % to 100 mol. % of at least one rare earth oxide and up to 99 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         74 . The article of  claim 73 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         75 . The article of  claim 71 , wherein the rare earth oxide is selected from scandia, yttria, lanthana, ceria, praseodymia, neodymia, promethia, samaria, europia, gadolinia, terbia, dysprosia, holmia, erbia, thulia, ytterbia, lutetia, and combinations thereof. 
     
     
         76 . The article of  claim 71 , wherein the CMAS-resistant layer overlies at least a portion of the substrate, wherein the CMAS-resistant layer comprises a first surface adjacent the substrate and a second surface opposite the substrate, and wherein the CMAS-resistant layer reacts with CMAS to form a reaction product layer on the second surface of the CMAS-resistant layer. 
     
     
         77 . The article of  claim 71 , wherein the article further comprises a bond coat, and wherein the bond coat is adjacent the substrate and the CMAS-resistant layer is adjacent the bond coat. 
     
     
         78 . The article of  claim 71 , wherein the article further comprises an environmental barrier coating (EBC), and wherein the EBC is adjacent the substrate and the CMAS-resistant layer is adjacent the EBC. 
     
     
         79 . The article of  claim 71 , wherein the article further comprises an environmental barrier coating (EBC) and a bond coat, and wherein the bond coat is adjacent the substrate, the EBC is adjacent the bond coat, and the CMAS-resistant layer is adjacent the EBC. 
     
     
         80 . The article of  claim 79 , wherein the article further comprises a transitional layer, wherein the transitional layer is adjacent the EBC and the CMAS-resistant layer is adjacent the transitional layer, and wherein the transitional layer comprises a mixture of components of the EBC and components of the CMAS-resistant layer. 
     
     
         81 . The article of  claim 71 , wherein the article further comprises a thermal barrier coating (TBC), and wherein the TBC is adjacent the substrate and the CMAS-resistant layer is adjacent the TBC. 
     
     
         82 . The article of  claim 81 , wherein the article further comprises a transitional layer wherein the transitional layer is adjacent the TBC and the CMAS-resistant layer is adjacent the transitional layer, and wherein the transitional layer comprises a mixture of components of the TBC and components of the CMAS-resistant layer. 
     
     
         83 . The article of  claim 71 , wherein the article further comprises a thermal barrier coating (TBC) and a bond coat, and wherein the bond coat is adjacent the substrate, the TBC is adjacent the bond coat, and the CMAS-resistant layer is adjacent the TBC. 
     
     
         84 . The article of  claim 83 , wherein the article further comprises a transitional layer, wherein the transitional layer is adjacent the TBC and the CMAS-resistant layer is adjacent the transitional layer, and wherein the transitional layer comprises a mixture of components of the TBC and components of the CMAS-resistant layer. 
     
     
         85 . An article comprising:
 a substrate;   a bond coat on the substrate; and   a CMAS-resistant layer on the bond coat, wherein the CMAS-resistant layer comprises a rare earth oxide and is essentially free of zirconia and hafnia.   
     
     
         86 . The article of  claim 85 , wherein the CMAS-resistant layer further comprises at least one of alumina, silica, and combinations thereof. 
     
     
         87 . The article of  claim 86 , wherein the CMAS-resistant layer comprises 1 mol. % to 100 mol. % of at least one rare earth oxide and up to 99 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         88 . The article of  claim 87 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         89 . The article of  claim 86 , wherein the CMAS-resistant layer comprises 10 mol. % to 90 mol. % of at least one rare earth oxide, and 10 mol. % to 90 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         90 . The article of  claim 89 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         91 . The article of  claim 86 , wherein the CMAS-resistant layer comprises 20 mol. % to 80 mol. % of at least one rare earth oxide and 20 mol. % to 80 mol. % of at least one of alumina, silica and combinations thereof, with a total of 100 mol. %. 
     
     
         92 . The article of  claim 91 , wherein the CMAS-resistant layer further comprises 1 mol. % to 30 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         93 . The article of  claim 85 , wherein the rare earth oxide is selected from the group consisting of oxides of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and combinations thereof. 
     
     
         94 . The article of  claim 85 , wherein the bond coat comprises at least one of: a MCrAlY alloy, wherein M is selected from Ni, Co, and NiCo; a β-NiAl alloy; a γ-Ni+γ′-Ni 3 Al alloy; mullite, silicon, and combinations thereof. 
     
     
         95 . The article of  claim 94 , wherein the β-NiAl alloy further comprises at least one of Pt, Cr, Hf, Zr, Y, Si, and combinations thereof. 
     
     
         96 . The coating of  claim 94 , wherein the γ-Ni+γ′-Ni3Al alloy further comprises at least one of Pt, Cr, Hf, Zr, Y, Si, and combinations thereof. 
     
     
         97 . The article of  claim 85 , wherein the substrate comprises at least one of a superalloy or a ceramic matrix composite (CMC). 
     
     
         98 . An article comprising:
 a substrate comprising a ceramic matrix composite or a ceramic; and   a coating comprising a CMAS-resistant layer comprising a rare earth oxide, wherein the CMAS-resistant layer is essentially free of zirconia and hafnia.   
     
     
         99 . The article of  claim 98 , wherein the CMAS-resistant layer further comprises at least one of silica or alumina. 
     
     
         100 . The article of  claim 99 , wherein the CMAS-resistant layer comprises silica, and wherein at least some of the silica and at least some of the rare earth oxide form at least one of a rare earth monosilicate or a rare earth disilicate. 
     
     
         101 . The article of  claim 99 , wherein the CMAS-resistant layer comprises 1 mol. % to 100 mol. % of at least one rare earth oxide and up to 99 mol. % of at least one of alumina or silica. 
     
     
         102 . The article of  claim 101 , wherein the CMAS-resistant layer further comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         103 . The article of  claim 99 , wherein the CMAS-resistant layer comprises 10 mol. % to 90 mol. % of at least one rare earth oxide and 10 mol. % to 90 mol. % of at least one of alumina or silica. 
     
     
         104 . The article of  claim 103 , wherein the CMAS-resistant layer comprises 0.1 mol. % to 50 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         105 . The article of  claim 99 , wherein the CMAS-resistant layer comprises 20 mol. % to 80 mol. % of at least one rare earth oxide and 20 mol. % to 80 mol. % of at least one of alumina or silica. 
     
     
         106 . The article of  claim 105 , wherein the CMAS-resistant layer further comprises 1 mol. % to 30 mol. % of an additive component selected from Ta 2 O 5 , HfSiO 4 , alkali oxides, alkali earth oxides, and combinations thereof. 
     
     
         107 . The article of  claim 98 , wherein the rare earth oxide is selected from the group consisting of oxides of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and combinations thereof. 
     
     
         108 . The article of  claim 98 , wherein the CMAS-resistant layer comprises a thickness of about 0.1 mil to about 60 mil. 
     
     
         109 . The article of  claim 98 , wherein the CMAS-resistant layer comprises a thickness of about 0.5 mil to about 15 mil. 
     
     
         110 . The article of  claim 98 , wherein the coating further comprises a second layer comprising at least one of mullite, silicon, barium strontium aluminosilicate, calcium aluminosilicate, cordierite, lithium aluminosilicate, or a rare earth silicate, wherein the CMAS-resistant layer is adjacent to the second layer. 
     
     
         111 . The article of  claim 110 , wherein the second layer comprises silicon. 
     
     
         112 . The article of  claim 111 , wherein the CMAS-resistant layer comprises a rare earth silicate. 
     
     
         113 . The article of  claim 110 , further comprising a transitional layer, wherein the transitional layer is adjacent to the second layer and wherein the CMAS-resistant layer is adjacent to the transitional layer.