Environmental barrier coating and method of forming the same
A method of applying a coating to a substrate includes forming a slurry by mixing elemental precursors of gettering particles, diffusive particles, matrix material, and a carrier fluid; applying the slurry to a substrate; and sintering the slurry to form a composite material. The sintering causes the elemental precursors to react with one another to form gettering particles. An article is also disclosed.
1. A method of applying a coating to a substrate, comprising:
forming a slurry by mixing elemental precursors of gettering particles, diffusive particles, matrix material, and a carrier fluid;
applying the slurry to a substrate; and
sintering the slurry to form a composite material, whereby the sintering causes the elemental precursors to react with one another to form gettering particles.
2. The method of claim 1 , wherein the elemental precursors include silicon and the gettering particles are intermetallic silicides.
3. The method of claim 2 , wherein the elemental precursors include silicon and a refractory metal.
4. The method of claim 1 , further comprising the step of applying a topcoat.
5. The method of claim 4 , wherein the step of applying the topcoat is performed before the step of sintering the slurry.
6. The method of claim 1 , wherein the sintering is performed at a temperature between about 1000° C. and 1400° C. in an inert atmosphere.
7. The method of claim 1 , further comprising the step of subjecting the slurry to a low-heat treatment prior to the sintering step, and wherein sintering step is performed at a first temperature, and the low-heat treatment is performed at a second temperature lower than the first temperature.
8. The method of claim 1 , wherein after the mixing step, the elemental precursors are embedded in one another.
9. The method of claim 1 , wherein after the applying step, the elemental precursors are in an interconnected matrix.
10. The method of claim 1 , wherein after the sintering step, the gettering particles have a platelet shape.
11. The method of claim 10 , where the gettering particles have a major axis that is generally parallel to a surface of the substrate.
12. The method of claim 11 , wherein after the sintering step, the gettering particles are arranged in an interconnected matrix.
13. The method of claim 1 , wherein the slurry is aqueous.
14. The method of claim 1 , wherein the substrate is a ceramic matrix composite material.