Interface materials for damage-tolerant oxide composites

Several approaches for designing damage tolerant, refractory oxide composites are reviewed. The most promising approaches make use of fiber coatings of rare-earth orthophosphates (monazite or xenotime), aligned layer structures (beta-aluminas/magnetoplumbites), or porous layers (or porous matrices). Observations of the fracture behavior and compatibility of LaPO4 coatings in alumina and alumina-zirconia systems are discussed, and preliminary property measurements are presented for composites consisting of alumina fibers in a two-phase matrix of alumina and LaPO4.