Binder-free coating for refractory ceramics

摘要

A novel coating for refractory ceramic surfaces involves: (a) application of an aqueous solution of a thermally unstable salt, selected from Sc, La and/or Y salts, onto a refractory oxide-ceramic, nitride-ceramic or silicon carbide ceramic; (b) dewatering and heating to above the metal salt decomposition temperature; and (c) sintering the product in conventional manner. Also claimed are (i) a coated refractory ceramic casting mould obtained by the above process; and (ii) methods of producing the coated refractory ceramic casting mould.