Damage tolerant ceramic matrix composites by a precursor infiltration

Abstract

Damage-tolerant, continuous fiber ceramic matrix composites are fabricated to fill the space between the fibers with a powder. The powder particles are heat treated to form a porous framework without shrinkage, which is then strengthened with an inorganic synthesized from a precursor in solution. High particle packing densities is achieved within the fiber preform using a small particle-to-fiber diameter ratio. Filling the interstices with a powder increases the composite density and also limits the size of the crack-like voids within the matrix. The ceramic matrix composite (CMC) has mechanical characteristics similar to those found in wood. It is also affordable and inherently oxidation resistant. The composite is characterized by a heterogeneous distribution of fibers within a porous matrix having a homogeneous, fine porosity. A residual stress from thermal expansion mismatch of the matrix and fibers is created in the composite. The illustrated embodiment uses Al.sub.2 O.sub.3 fibers with either mullite or Si.sub.3 N.sub.4 matrices.

Dependencies are inferred from the claim text.