Environmental barrier coating and method of applying the same
An article includes a substrate, a barrier layer disposed on the substrate, and an oxide-based ceramic material topcoat disposed on the barrier layer. The topcoat includes at least one crack. The article also includes a filler layer disposed on the topcoat and in the at least one crack. A method of applying a coating to an article and an article are also disclosed.
1 . An article, comprising:
a substrate;
a barrier layer disposed on the substrate;
an oxide-based ceramic material topcoat disposed on the barrier layer, the topcoat including at least one crack; and
a filler layer disposed on the topcoat and in the at least one crack,
wherein an overall density of the filler layer is higher than an overall density of the topcoat,
wherein the at least one crack has a width less than about 100 nm.
2 . The article of claim 1 , wherein the barrier layer is a composite material, the composite material including a matrix, diffusive particles dispersed in the matrix, and gettering particles dispersed in the matrix.
3 . The article of claim 1 , wherein the barrier layer is a monolithic layer.
4 . The article of claim 1 , wherein the filler layer has a coefficient of thermal expansion less than about 6×10 −6 K −1 .
5 . The article of claim 1 , wherein the filler layer has a thickness of between about 1 and about 2 microns.
6 . The article of claim 1 , wherein the crack has an aspect ratio of at least about 100:1.
7 . The article of claim 1 , wherein the at least one crack is a through-thickness crack that extends in a direction approximately parallel to a thickness dimension of the topcoat.
8 . The article of claim 7 , wherein the through-thickness crack extends through the entire thickness dimension.
9 . The article of claim 1 , wherein the topcoat includes a ytterbium-based oxide.
10 . The article of claim 1 , wherein the filler layer includes HfO 2 .
11 . The article of claim 1 , wherein the filler layer includes Al 2 O 3 .
12 . The article of claim 1 , wherein the filler layer has a modulus of elasticity less than about 200 GPa.
13 . An article, comprising:
a substrate;
an oxide-based ceramic material topcoat disposed on the substrate, the topcoat including at least one crack; and
a filler layer disposed on the topcoat and in the at least one crack,
wherein an overall density of the filler layer is higher than an overall density of the topcoat, and
wherein the at least one crack has a width less than about 100 nm.
14 . The article of claim 13 , wherein the at least one crack is a through-thickness crack that extends in a direction approximately parallel to a thickness dimension of the topcoat.
15 . The article of claim 14 , wherein the through-thickness crack extends through the entire thickness dimension.
16 . A method of applying a coating to an article, comprising:
disposing a barrier layer on a substrate;
disposing an oxide-based ceramic material topcoat on the barrier layer, the topcoat including at least one crack; and
disposing a filler layer on the topcoat and in the at least one crack,
wherein the at least one crack has a width less than about 100 nm, and
wherein an overall density of the filler layer is higher than an overall density of the topcoat.
17 . The method of claim 16 , wherein the barrier layer is a monolithic layer.
18 . The method of claim 16 , wherein the filler layer is disposed on the topcoat by atomic layer deposition.
19 . The method of claim 16 , wherein the filler layer is disposed on the topcoat by slurry coating.
20 . The method of claim 16 , wherein the filler layer is disposed on the topcoat by chemical vapor deposition.