Sintering silicon nitride compacts in powder packing - in nitrogen at atmospheric pressure, without wt. loss

摘要

A sintered Si3N4 article is prepd. By (a) sintering an Si3 N4 compact, density =1.3 g/cm3 in N2 at atmospheric pressure with the compact embedded in a protectice powder of Si3N4 and/or BN and 3-20 wt.% sinterisation additive(s) for Si3N4. Sintered compacts of high density and homogeneity can be formed with thermal decompsn. limited without using atmospheric pressure, e.g. a compact having density 3.05 g/cm3 was prepd. with wt. loss 0.5 wt.% and no detectable structural dishomogeneities.