Powder processing of mullite/Mo functionally graded materials

Graded or layered materials have been used for many years in specific applications to improve reliability for bonds between dissimilar materials, for improved coating adherence and to obtain better compatibility between fibers and matrices ices in composites. Recently, the concept has been formalized en, and such materials entitled FGMs. Molybdenum and mullite are two ideal candidates to fabricate ceramic/metal composites and FGMs because of their similarity in thermal expansion, lack of reactivity at high temperature and high refractoriness. In the present work a systematic investigation of powder processing for the fabrication of mullite/Mo FGMs is described. it,vas found that the processing of mullite/Mo in water resulted in a formation of a homogeneous composite, whereas mixtures processed in ethyl alcohol produced FGMs with continuous gradient. Compositional gradients, fracture toughness, hardness and Electrical conductivity of the FGMs were also evaluated. (C) 1998 Elsevier Science Limited All rights reserved.