Environmental barrier coating
An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix, diffusive particles, and gettering particles. The gettering particles include at least one of non-gas-evolving particles and porous particles. An article and a method are also disclosed.
1. An article comprising:
a ceramic-based substrate; and
a barrier layer on the ceramic-based substrate, the barrier layer including a matrix, diffusive particles, and gettering particles, wherein the gettering particles include non-gas-evolving particles, wherein the non-gas-evolving particles have a protective coating, and wherein the protective coating is operable to limit reactivity of the non-gas-evolving particles.
2. The article of claim 1 , wherein the non-gas evolving particles comprise at least 30% of the gettering particles.
3. The article of claim 1 , wherein the non-gas evolving particles include at least one of metallic particles, silicide particles, aluminide particles, boride particles, and a mixture thereof.
4. The article of claim 1 , wherein the gettering particles further include porous particles, and wherein the porous particles include a shell surrounding a hollow core.
5. The article of claim 4 , wherein the shell comprises a silicon- or boron-containing material that is reactive with oxygen or water.
6. The article of claim 1 , wherein the gettering particles further include porous particles, and wherein the porous particles are an agglomerate of sub-particles.
7. The article of claim 6 , wherein the sub-particles are hollow shells in a matrix.
8. The article of claim 1 , wherein the gettering particles further include porous particles, and wherein the porosity of the porous particles is between about 30-70%.
9. The article of claim 1 , wherein the diffusive particles are barium-magnesium alumino-silicate particles.
10. The article of claim 1 , wherein the gettering particles include silicon oxycarbide particles.
11. The article of claim 1 , further comprising a ceramic-based topcoat on the barrier layer.
12. The article of claim 1 , further comprising an intermediate layer between the barrier layer and the substrate, wherein the intermediate layer comprises gettering particles in a matrix.
13. The article of claim 1 , wherein the article is an airfoil, combustor wall or blade outer seal for a gas turbine engine.
14. The article of claim 1 , wherein the coating of the non-gas-evolving particles is silica.
15. The article of claim 1 , wherein the non-gas-evolving particles are MoSi 2 particles or WSi 2 particles.
16. An article, comprising:
a ceramic-based substrate;
a barrier layer on the ceramic-based substrate, the barrier layer including a matrix, barium-magnesium alumino-silicate particles, and gettering particles, wherein the gettering particles include non-gas-evolving particles, wherein the non-gas-evolving particles have a protective coating, and wherein the protective coating is operable to limit reactivity of the non-gas-evolving particles;
an intermediate layer between the barrier layer and the ceramic-based substrate, the intermediate layer including gettering particles in a matrix; and
a ceramic-based topcoat on in the barrier layer.
17. The article of claim 16 , wherein the non-gas evolving particles comprise at least 30% of the gettering particles in the barrier layer.
18. The article of claim 16 , wherein the non-gas evolving particles include at least one of metallic particles, silicide particles, aluminide particles, boride particles, and a mixture thereof.
19. The article of claim 16 , wherein the gettering particles further include porous particles, and wherein the porous particles include a shell surrounding a hollow core.
20. The article of claim 16 , wherein the gettering particles further include porous particles, and wherein the porous particles are an agglomerate of hollow sub-particles in a matrix.