US Patent 7745022 CMC with multiple matrix phases separated by diffusion barrier

A ceramic matrix composite (CMC) material (10) with increased interlaminar strength is obtained without a corresponding debit in other mechanical properties. This is achieved by infusing a diffusion barrier layer (20) into an existing porous matrix CMC to coat the exposed first matrix phase (19) and fibers (12), and then densifying the matrix with repeated infiltration cycles of a second matrix phase (22). The diffusion barrier prevents undesirable sintering between the matrix phases and between the second matrix phase and the fibers during subsequent final firing and use of the resulting component (30) in a high temperature environment.