Sintering of mullite–β-eucryptite ceramics with very low thermal expansion

Abstract

Abstract Sintering of composite ceramic materials with an appropriate proportion of mullite and β-eucryptite to obtain a very low thermal expansion material has been tested by conventional and spark plasma sintering methods. The adjustment of the thermal expansion coefficient of the composites was performed by means of dilatometries and modifying the mullite–β-eucryptite proportions in the starting materials. Control of the reactivity between both phases at high temperature is the key to controlling not only the sinterability of the composites in the solid state, but also to controlling the final expansion properties of the material. X-ray diffraction with Rietveld refinement and field emission scanning microscopy have been used to characterize the sintered materials, together with some mechanical characterization.