Heat treatment was performed on beta -SIC with different sintering additive
s in the temperature range 1873-2073 K, in both argon and nitrogen-gas atmo
spheres. In the case of the specimens heat-treated at 2073 K in argon, the
weight loss was more than the total weight of the sintering additives, exce
pt for B,C-doped beta -SIC. On the other hand, weight loss was suppressed b
y about one-third to one-half in nitrogen gas. Weight loss depended mainly
on the reaction at the interface between the SiC grains and the grain-bound
ary phase.