Atomic layer deposition method enhancing the nucleation and crystallinity of a boron nitride interface coating on a silicon carbide fiber
A method of forming a ceramic matrix composite includes arranging a plurality of fibers into a preform, each of the plurality of fibers being formed from silicon carbide, depositing a nucleating layer on the plurality of fibers, the nucleating layer comprising a crystalline material having an a-lattice constant and a c-lattice constant, and depositing a boron nitride layer on the nucleating layer. The c-lattice constant of the crystalline material of the nucleating layer corresponds to an a-lattice constant of the silicon carbide, such that the c-lattice constant of the crystalline material is within 3.0% of the a-lattice constant of the silicon carbide.
1 . A method of forming a ceramic matrix composite, the method comprising:
arranging a plurality of fibers into a preform, each of the plurality of fibers being formed from silicon carbide;
depositing a nucleating layer on the plurality of fibers, the nucleating layer comprising a crystalline material having an a-lattice constant and a c-lattice constant, wherein the crystalline material comprises ruthenium; and
depositing a boron nitride layer on the nucleating layer;
wherein the c-lattice constant of the crystalline material of the nucleating layer corresponds to an a-lattice constant of the silicon carbide, such that the c-lattice constant of the crystalline material is within 3.0% of the a-lattice constant of the silicon carbide.
2 . The method of claim 1 , wherein the boron nitride layer comprises an amount of hexagonal boron nitride, the hexagonal boron nitride having an a-lattice constant corresponding to the a-lattice constant of the crystalline material of the nucleating layer, such that the a-lattice constant of hexagonal boron nitride is within 8.0% of the a-lattice constant of the crystalline material.
3 . The method of claim 1 , wherein the boron nitride layer further comprises an amount of turbostratic boron nitride, the turbostratic boron nitride having an a-lattice constant corresponding to the a-lattice constant of the crystalline material of the nucleating layer, such that the a-lattice constant of turbostratic boron nitride is within 8.0% of the a-lattice constant of the crystalline material.
4 . The method of claim 1 , wherein the a-lattice constant of ruthenium is 2.7 angstroms, and wherein the c-lattice constant of ruthenium is 4.3 angstroms.
5 . The method of claim 4 , wherein the a-lattice constant of hexagonal boron nitride ranges from 2.5 angstroms to 2.9 angstroms.
6 . The method of claim 4 , wherein the silicon carbide is β-silicon carbide.
7 . The method of claim 6 , wherein the c-lattice constant of the B-silicon carbide is 4.4 angstroms.
8 . The method of claim 2 , wherein the nucleating layer is deposited using atomic layer deposition.
9 . The method of claim 2 , wherein the boron nitride layer is deposited using chemical vapor infiltration.
10 . The method of claim 2 , wherein the nucleating layer is deposited such that it has a uniform thickness ranging from 2 nanometers to 20 nanometers.
11 . The method of claim 10 , wherein the thickness ranges from 5 nanometers to 10 nanometers.
12 . The method of claim 2 and further comprising: densifying the preform with a ceramic matrix.
13 . The method of claim 12 , wherein densifying the preform comprises at least one of: chemical vapor infiltration, slurry infiltration, melt infiltration, and polymer infiltration and pyrolysis.
14 . The method of claim 12 and further comprising: prior to the step of densifying the preform, depositing a further layer on the boron nitride layer comprising at least one of: silicon-doped boron nitride, silicon nitride, carbon, silicon carbide, and boron nitride.
15 . A method of forming a ceramic matrix composite, the method comprising:
arranging a plurality of fibers into a preform, each of the plurality of fibers being formed from silicon carbide;
depositing a nucleating layer on the plurality of fibers, the nucleating layer comprising a crystalline material comprising ruthenium, the crystalline material having an a-lattice constant and a c-lattice constant; and
depositing a boron nitride layer on the nucleating layer, the boron nitride comprising hexagonal boron nitride and turbostratic boron nitride;
wherein the a-lattice constant of the crystalline material of the nucleating layer corresponds to an a-lattice constant of each of the hexagonal boron nitride and turbostratic boron nitride, such that the a-lattice constant of the crystalline material is within 8.0% of the a-lattice constant of each of the hexagonal boron nitride and turbostratic boron nitride.
16 . The method of claim 15 , wherein the c-lattice constant of the crystalline material of the nucleating layer corresponds to an a-lattice constant of the silicon carbide, such that the c-lattice constant of the crystalline material is within 3.0% of the a-lattice constant of the silicon carbide.
17 . The method of claim 16 , wherein the silicon carbide is β-silicon carbide.
18 . The method of claim 15 and further comprising: densifying the preform with a ceramic matrix.