Dense layered molybdenum disilicide-silicon carbide functionally graded composites formed by field-activated synthesis

Dense, layered, single- and graded-composition composites of MoSi2 and SIC were formed from elemental powders in one step, using the field-activated p ressure-assisted combustion method. Compositions ranging from 100% MoSi2 to 100% SiC were synthesized, with relative densities ranging from 99% to 76% , respectively, X-ray diffractometry results indicated the formation of pur e phases when the concentration of MoSi2 was high and the appearance of a t ernary phase, Mo4.8Si3C0.6, when the concentration of SIC was high. Electro n microprobe analysis results showed the formation of stoichiometric and un iformly distributed phases. A layer-to-layer variation in composition of 10 mol% was sufficient to prevent thermal cracking during formation of the la yered functionally graded materials.