Process for the manufacture of a rigid insulating refractory material and material thus obtained

摘要

Process for the manufacture of a rigid insulating refractory material capable of working in contact with a molten metal, in which: - first of all, a base refractory ceramic material is impregnated with a solution of a precursor of a refractory oxide; - then, the impregnated ceramic material is dried; - and finally this dried material is pyrolysed; characterised: - in that the precursor is a rare-earth salt or sol; - in that the base refractory ceramic material is a highly porous material which has a porosity of between 75 and 95%; - and in that pyrolysis is carried out at a temperature of between 800 and 1000@C for two to six hours, so that the walls of the pores of the base ceramic material are covered with a fine protective layer of rare-earth oxides. Applications: moulds for casting iron- or copper-based alloys.