Effects of containing crucibles on microstructure of Si3N4

The effects of the sample containing crucible composition on the microstructure of sintered Si3N4 have been studied. Crucibles made of graphite and boron nitride, which created different gas environments during sintering, were selected for comparison. Samples sintered in graphite crucibles had a higher density, higher aspect ratio, wider grain size distribution, and more large grains than samples sintered in BN crucibles. The type of crucible used exerted a direct influence on the sintering atmosphere, chemical composition, and viscosity of the grain boundary phase and also had substantial effects on the resulting microstructure and mechanical properties. (C) 1996 The Institute of Materials.