Environmental barrier fiber coating
A fiber having an environmental barrier coating is provided that includes, in one illustrative form, a Hi Nicalon preform assembled in a tooling for chemical vapor infiltration and cleaned to remove sizing char from fibers of the Hi Nicalon preform; a ytterbium doped silicon carbide coat located over the Hi Nicalon preform; a boron nitride interface coat applied over the ytterbium doped silicon carbide coat; and a silicon carbide coat applied over the boron nitride interface coat.
1. Fibers having an environmental barrier coating, comprising:
a fiber preform;
a ytterbium doped silicon carbide coat located directly on the fiber preform;
a boron nitride interface coat applied over the ytterbium doped silicon carbide coat; and
a silicon carbide coat applied over the boron nitride interface coat.
2. The fibers having the environmental barrier coating of claim 1 , wherein the boron nitride interface coat has a thickness of about 0.5 μm.
3. The fibers having the environmental barrier coating of claim 1 , wherein the silicon carbide coat has a thickness of about 2 μm.
4. The fibers having the environmental barrier coating of claim 1 , wherein the fiber preform includes about 36% fiber volume.
5. The fibers having the environmental barrier coating of claim 1 , wherein the preform is completed with slurry and melt infiltration.
6. The fibers having the environmental barrier coating of claim 1 , wherein the ytterbium doped silicon carbide coat is applied by chemical vapor infiltration.
7. The fibers having the environmental barrier coating of claim 1 , wherein the silicon carbide coat is applied by chemical vapor infiltration.
8. The fibers of claim 1 , wherein the fiber preform comprises carbon fibers, silicon carbide fibers, alumina fibers, aluminosilicate fibers, SiNC fibers or glass fibers.
9. The fibers of claim 8 , wherein the fiber preform comprises silicon carbide fibers.
10. The fibers of claim 9 , wherein the silicon carbide fibers comprise Hi Nicalon fibers.
11. The fibers of claim 1 , wherein the fiber preform does not include sizing char.