Hafnon and zircon environmental barrier coatings for silicon-based components
A method for coating a substrate includes spraying a combination of powders. The combination of powders includes: Hf 0.5 Si 0.5 O 2 ; Zr 0.5 Si 0.5 O 2 ; and, optionally, at least one of HfO 2 and ZrO 2 . A molar ratio of said Hf 0.5 Si 0.5 O 2 and HfO 2 combined to said Zr 0.5 Si 0.5 O 2 and ZrO 2 combined is from 2:1 to 4:1. A molar ratio of said Hf 0.5 Si 0.5 O 2 to said HfO 2 is at least 1:3.
1 . A coated substrate comprising:
a substrate; and
a coating layer atop the substrate and comprising:
at least 25.0 volume %, exclusive of porosity, a first phase being a solid solution of Hf 1-x Zr x SiO 4 ; and
at least 25.0 volume %, exclusive of porosity, a second phase being a solid solution of Hf 1-y Zr y O 2 .
2 . The coated substrate of claim 1 wherein:
the substrate is a CMC; and
the substrate is silicon-based.
3 . The coated substrate of claim 1 wherein:
a bond coat is between the substrate and the coating layer.
4 . The coated substrate of claim 1 wherein the coating layer comprises:
at least 50.0 volume %, exclusive of porosity, said first phase; and
at least 25.0 volume %, exclusive of porosity, said second phase.
5 . The coated substrate of claim 1 wherein:
the x in the Hf 1-x Zr x SiO 4 is between 0.20 and 0.40 inclusive; and
the y in the Hf 1-y Zr y O 2 is less than the x.
6 . The coated substrate of claim 1 wherein:
the layer is between the substrate and a second coating layer.
7 . The coated substrate of claim 6 wherein:
the second coating layer comprises:
at least 25.0 volume %, exclusive of porosity, a first phase being a solid solution of Hf 1-x Zr x SiO 4 ; and
at least 5.0 volume %, exclusive of porosity, a second phase being a solid solution of Hf 1-y Zr y O 2 , wherein the second coating layer has a lower volume ratio of the Hf 1-y Zr y O 2 to the Hf 1-x Zr x SiO 4 than does the coating layer.
8 . The coated substrate of claim 6 wherein:
the second coating layer comprises:
at least 25.0 volume %, exclusive of porosity, a first phase being a solid solution of Hf 1-x Zr x SiO 4 ; and
at least 5.0 volume %, exclusive of porosity, a second phase being a solid solution of Hf 1-y Zr y O 2 , wherein the second coating layer further comprises a dislocator phase as a third phase.
9 . The coated substrate of claim 8 wherein:
the dislocator phase is present at 2.0% to 40.0% total volume in the second coating layer.
10 . The coated substrate of claim 9 wherein:
the dislocator phase comprises alkaline earth or transition metal (M) tungstates (MWO 4 ), alkaline earth molybdates (MMoO 4 ), rare earth (RE) phosphates (REPO 4 ) and combinations thereof at said 2.0% to 40.0% total volume in the second coating layer.
11 . The coated substrate of claim 10 wherein:
the dislocator phase comprises rare earth (RE) phosphates (REPO 4 ) at said 2.0% to 40.0% total volume in the second coating layer.
12 . The coated substrate of claim 6 wherein the second coating layer comprises:
at least 25.0 volume %, exclusive of porosity, a first phase being a solid solution of Hf 1-x Zr x SiO 4 ; and
at least 25.0 volume %, exclusive of porosity, a second phase being a solid solution of Hf 1-y Zr y O 2 ,
wherein:
the x in the Hf 1-x Zr x SiO 4 is between 0.20 and 0.40 inclusive; and
the y in the Hf 1-y Zr y O 2 is less than the x.
13 . The coated substrate of claim 6 wherein:
the second layer has a greater porosity than said layer.
14 . The coated substrate of claim 1 wherein:
the layer is an outermost layer.
15 . The coated substrate of claim 14 being a blade outer airseal (BOAS) segment.
16 . The coated substrate of claim 15 wherein,
the coating layer further comprises a dislocator phase as a third phase.
17 . The coated substrate of claim 16 wherein,
the third phase comprises alkaline earth or transition metal (M) tungstates (MWO 4 ), alkaline earth molybdates (MMoO 4 ), rare earth (RE) phosphates (REPO 4 ) and combinations thereof at 2.0% to 40.0% total volume in the coating layer.
18 . The coated substrate of claim 16 wherein,
the third phase comprises alkaline earth or transition metal (M) tungstates (MWO 4 ), alkaline earth molybdates (MMoO 4 ), rare earth (RE) phosphates (REPO 4 ) and combinations thereof at 5.0% to 20.0% total volume in the coating layer.
19 . The coated substrate of claim 15 in combination with a blade of a stage of blades facing, the blade having a tip facing an inner diameter (ID) face of the BOAS segment.
20 . The coated substrate of claim 1 wherein,
the coating layer further comprises a dislocator phase as a third phase; and
the third phase comprises alkaline earth or transition metal (M) tungstates (MWO 4 ), alkaline earth molybdates (MMoO 4 ), rare earth (RE) phosphates (REPO 4 ) and combinations thereof at 2.0% to 40.0% total volume in the coating layer.