FACTORS AFFECTING THE FORMATION RATE OF ZRN BY THE CARBOTHERMAL NITRIDATION METHOD

Factors affecting the formation rate of zirconium nitride by the carbo thermal nitridation method were studied. Use of finer particle-sized z irconia powder showed the higher formation rate of zirconium nitride. A single-phase of zirconium nitride with cubic symmetry was obtained b y firing graphite and zirconia (0.35 mu m) mixed compact with a molar ratio C/ZrO2=4 at 1400 degrees C for 12h in flowing nitrogen gas. The formation process of zirconium nitride was in competition with partial nitridation of zirconia, occurring in the nontransformable tetragonal zirconia phase. It was not possible to obtain stoichiometric and pure ZrN by carbothermal nitridation method. The presence of ZrN seed crys tals restrained the formation of zirconium nitride.