Environmental barrier coating
An example article according to the present disclosure includes, among other possible things, a metallic substrate, and a bond coat on the metallic substrate. The bond coat includes a matrix phase, gettering particles in the matrix phase, wherein the gettering particles are reactive with oxidants, and a dispersion of matrix modifier particles in the matrix phase. The example article also includes a diffusion barrier between the bond coat and the metallic substrate, wherein the diffusion barrier is configured to inhibit diffusion of components from the bond coat into the metallic substrate. An example composite material and method of applying a barrier to a substrate are also disclosed.
1. An article comprising:
a metallic substrate; and
a bond coat on the metallic substrate, the bond coat including:
a matrix phase,
gettering particles in the matrix phase, wherein the gettering particles are reactive with oxidants, and
a dispersion of matrix modifier particles in the matrix phase; and
a diffusion barrier between the bond coat and the metallic substrate, wherein the diffusion barrier is configured to inhibit diffusion of components from the bond coat into the metallic substrate.
2. The article as recited in claim 1 , wherein the metallic substrate is a refractory metal substrate.
3. The article as recited in claim 1 , wherein the metallic substrate comprises at least one of molybdenum, niobium, tantalum, tungsten, vanadium, chromium, zirconium, hafnium, and alloys thereof.
4. The article as recited in claim 1 , wherein the metallic substrate comprises a high entropy metal alloy.
5. The article as recited in claim 1 , wherein the diffusion barrier includes at least one of silicide, metal silicide, boride and borosilicide phases.
6. The article as recited in claim 1 , wherein the diffusion barrier has a density that is higher than the density of the bond coat.
7. The article as recited in claim 6 , wherein the density of the diffusion barrier is at least 10% higher than the density of the bond coat.
8. The article as recited in claim 1 , further comprising a ceramic-based top coat on the bond coat.
9. The article as recited in claim 1 , wherein the gettering particles include at least one metal silicide.
10. The article as recited in claim 9 wherein the metal silicide includes at least one of MoSi 2 and Mo 5 Si 3 .
11. The article as recited in claim 1 , wherein the matrix modifier particles enhance the mechanical stability of the bond coat.
12. The article as recited in claim 1 , wherein the matrix modifier particles provide self-healing to the bond coat.
13. The article as recited in claim 1 , wherein the bond coat has a first coefficient of thermal expansion and the substrate has a second coefficient of thermal expansion, and wherein the difference between the first and second coefficients of thermal expansion is less than about 3.5.
14. The article as recited in claim 1 , wherein the article is a component of a gas turbine engine.
15. The article as recited in claim 14 , wherein the article has at least one non-line-of-sight surface and at least one line-of-sight surface, and wherein the bond coat is disposed on the line-of-sight and the non-line-of-sight surfaces.
16. A composite material comprising:
a bond coat, the bond coat comprising:
a matrix,
a dispersion of gettering particles in the matrix, wherein the gettering particles are reactive with oxidants and include metal silicides, and
a dispersion of matrix modifier particles in the matrix; and
a diffusion barrier, wherein the diffusion barrier inhibits diffusion of components out of the bond coat.
17. The composite material as recited in claim 16 , wherein the diffusion barrier is on a first side of the bond coat, and further comprising a ceramic-based top coat on a second side of the bond coat.
18. The composite material as recited in claim 16 , wherein the diffusion barrier has a first density and the bond coat has a second density, and the first density is higher than the second density.