Layered interface coating for improved fiber protection and matrix crack sealing

A coated fiber structure for use in a ceramic matrix composite, the coated fiber structure comprising:

• a fiber extending along a fiber axis;
• and
• an interface coating arrangement applied to and circumscribing the fiber, the interface coating arrangement comprising:
• a first boron nitride layer extending coaxially about and in direct contact with the fiber;
• a first silicon-doped boron nitride layer extending coaxially about and in direct contact with the first boron nitride layer;
• a carbon layer extending coaxially about and in direct contact with the first silicon-doped boron nitride layer;
• a second boron nitride layer extending coaxially about and in direct contact with the carbon layer;
• and
• a second silicon-doped boron nitride layer extending coaxially about and in direct contact with the second boron nitride layer;
• wherein a silicon content of the first silicon-doped boron nitride layer is higher than the silicon content of the second silicon-doped boron nitride layer and wherein the silicon content of the first silicon-doped boron nitride layer ranges from 15 wt % to 30 wt %, and wherein the silicon content of the second silicon-doped boron nitride layer ranges from 5 wt % to 15 wt %.