Sintering of Al–Zr based oxide ceramics using thermal plasma

A novel and low cost extended arc thermal plasma heating (EATPH) reactor [Roul et al., JMSP 6 (1) (1998)] has been used to sinter Al–Zr oxide ceramics within a few minutes in Ar atmosphere instead of a few tens of hours by conventional furnace heating. Critical experimental parameters such as plasma power (kW), plasmagen gas flow rate, sintering time and electrode spacing distance are optimized to achieve high density sintered materials. It is noted that sintering time is approximately reciprocal to plasma power. Higher plasma power with less sintering time can generate high-density homogeneous material without significant grain growth. XRD and SEM studies were carried out to characterize and evaluate the sintered materials. Surface morphology revealed uniform particle size distribution in long-range order, with no runway grain growth during this EATPH sintering process. This simple EATPH method provides an alternative and quick technique for tailoring high temperature ceramic materials over conventional sintering method due to fast heat and mass transfer kinetics inside thermal plasma reactor.