Silicon oxycarbide 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 of barium-magnesium alumino-silicate or SiO 2 , a dispersion of silicon oxycarbide particles in the matrix, and a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO 2 , in the matrix.
1. An article comprising:
a ceramic-based substrate;
a barrier layer on the ceramic-based substrate, the barrier layer including a matrix of barium-magnesium alumino-silicate or SiO 2 , a dispersion of silicon oxycarbide particles in the matrix, the silicon oxycarbide particles having Si, O, and C in a covalently bonded network, and a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO 2 , in the matrix; and
a distinct intermediate layer between the barrier layer and the ceramic-based substrate, the distinct intermediate layer including an intermediate layer matrix of SiO 2 and a dispersion of intermediate layer silicon oxycarbide particles in the intermediate layer matrix.
2. The article as recited in claim 1 , wherein the barrier layer includes, by volume, 1-30% of the barium-magnesium alumino-silicate particles.
3. The article as recited in claim 1 , wherein the barrier layer includes, by volume, 30-94% of the silicon oxycarbide particles.
4. The article as recited in claim 1 , wherein the barrier layer includes, by volume, 5-40% of the matrix of SiO 2 .
5. The article as recited in claim 1 , wherein the barrier layer includes, by volume, 1-30% of the barium-magnesium alumino-silicate particles, 5-40% of the matrix of SiO 2 , and a balance of the silicon oxycarbide particles.
6. The article as recited in claim 5 , wherein the barrier layer includes, by volume, 1-5% of the barium-magnesium alumino-silicate particles.
7. The article as recited in claim 1 , wherein the silicon oxycarbide particles in the barrier layer have an average maximum dimension D 1 and the intermediate layer silicon oxycarbide particles in the distinct intermediate layer have an average maximum dimension D 2 , and D 2 is less than D 1 .
8. The article as recited in claim 1 , wherein the distinct intermediate layer includes, by volume, 5-40% of the intermediate layer matrix of SiO 2 and a balance of the dispersion of the intermediate layer silicon oxycarbide particles.
9. The article as recited in claim 1 , wherein the matrix of SiO 2 is continuous.
10. The article as recited in claim 1 , wherein the silicon oxycarbide particles have a composition SiO x M z C y , where M is at least one metal, x<2, y>0 and z<1 and x and z are non-zero.
11. The article as recited in claim 1 , wherein the silicon oxycarbide particles have an average maximum dimension of 1-75 micrometers.
12. The article as recited in claim 1 , further comprising a ceramic-based top coat on the barrier layer.
13. The article as recited in claim 1 , wherein the barrier layer consists of the matrix of SiO 2 , the dispersion of the silicon oxycarbide particles in the matrix, and the dispersion of the barium-magnesium alumino-silicate particles in the matrix.
14. A composite material comprising:
a matrix of barium-magnesium alumino-silicate or SiO 2 ;
a dispersion of silicon oxycarbide particles in the matrix, the silicon oxycarbide particles having Si, O, and C in a covalently bonded network; and
a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO 2 , in the matrix.
15. The composite material as recited in claim 14 , including, by volume, 1-30% of the barium-magnesium alumino-silicate particles, 5-40% of the matrix of SiO 2 , and a balance of the silicon oxycarbide particles.
16. The composite material as recited in claim 15 , including, by volume, 1-5% of the barium-magnesium alumino-silicate particles.
17. The composite material as recited in claim 14 , wherein the matrix of SiO 2 is continuous.