Inorganic sintered mouldings

摘要

Process for prodn. of an inorganic sintered moulding (I) comprises injection moulding or extruding a mixt. of a sinterable inorganic powder (II) and polyoxymethylene binder (III) to form a green moulding (IV), removing the binder (III) and sintering; the novelty is that (III) is removed by treatment of (IV) in a gaseous atmos. contg. an acid or BF3 gas. Treatment of (IV) is carried out at 20-150 deg.C; acid is HNO3, Halogen and/or an organic acid with b.pt. below 130 deg.C, pref. formic acid. (II) is, e.g. alumina, zirconia, yttrium oxide, SiC, Si3N4, Si powder, Fe powder, etc.; (III) is a homopolymer or copolymer of trioxan with ethylene oxide, 1,3-dioxolan, butanediol formal (V), etc., with mol.wt. 25,000-75,000.