Low thermal expansion cordierite ceramic contains a grain boundary alkaline earth, rare earth, gallium or indium compound

摘要

A low thermal expansion ceramic material comprises cordierite with a grain boundary precipitated crystalline compound containing one or more of alkaline earth elements (except magnesium), rare earth elements, gallium and indium. Independent claims are also included for (i) an article of the above ceramic material for use as a component used in semiconductor production; and (ii) production of a low thermal expansion ceramic material by subjecting a molding, comprising a cordierite component and an oxide or precursor containing one or more of alkaline earth elements (except magnesium), rare earth elements, gallium and indium, to either (a) firing at 1100-1500 deg C to achieve -95% sintered density and cooling from 1000 deg C at a cooling rate of }10 deg C/min. or (b) firing at 1300-1500 deg C to achieve -90% sintered density, hot hydrostatic treatment in an atmosphere of -100 at. at 1100-1400 deg C and cooling from 1000 deg C at a cooling rate of }10 deg C/min.