As a shrinkage of Ti(N, C)-30wt%Ni mixed powder compacts during sintering was remarkably promoted not only in vacuum, but also in argon, hydrogen and nitrogen atmosphere without an abnormal expansion, we concluded that the abnormal expansion during sintering of TiN-TiC-Ni mixed powder compacts¹⁾ was caused by denitrification which took place during the formation of Ti(N, C) solid solution.
Grain growth of sintered bodies was suppressed with an increase of nitrogen content of the nitrocarbide.
In sintering of TiN_x-TiC_y-30wt%Ni mixed powder compacts, the expansion was arrested; the composition showing the maximum sintered density in the sintering condition at 1500°C for 1 hr. was TiN_0.6-15wt%TiC-30wt%Ni.
Use of TiC_y powders also prevented the occurrence of the abnormal expansion during sintering.