Method for fabricating interface coatings

A coated substrate, comprising:

• a substrate including a ceramic fibrous preform having a coating deposited on, within and throughout the preform, the coating comprising the following structure:
• at least one layer of boron nitride disposed adjacent to the ceramic fibrous preform;
• at least one Si3N4-BN multilayer coating disposed adjacent to the boron nitride layer, the Si3N4-BN multilayer coating comprises a pattern of one or more alternating layers having:
• at least one layer of silicon nitride at a first thickness;
• at least one layer of boron nitride at a second thickness.

A method of fabricating a ceramic matrix composite, comprising:

• (i) providing at least one ceramic fibrous preform;
• and
• (ii) depositing on the substrate at least one layer of boron nitride;
• and
• (iii) depositing on the boron nitride layer a Si3N4-BN multilayer coating to form at least one coated ceramic fibrous preform, the Si3N4-BN multilayer coating comprises a pattern of alternating layers having at least one boron nitride layer and at least one silicon nitride layer according to the following steps:
• (iiia) depositing at a first deposition temperature a layer of silicon nitride at a first thickness;
• (iiib) depositing at a second deposition temperature a layer of boron nitride at a second thickness;
• and
• repeating steps (iiia) and (iiib) until forming the Si3N4-BN multilayer coating to form the at least one coated ceramic fibrous preform;
• (iv) depositing on the Si3N4-BN multilayer coating at least one layer of silicon carbide to form a partially densified ceramic matrix composite;
• (v) infiltrating a matrix material on and within the partially densified ceramic matrix composite;
• and
• (vi) densifying the matrix material on and within the partially densified ceramic matrix composite to form a ceramic matrix composite,
• wherein the Si3N4-BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.