Laser Melting of Spark Plasma-Sintered Zirconium Carbide: Thermophysical Properties of a Generation IV Very High-Temperature Reactor Material

摘要

Melting temperatures of zirconium carbide were investigated in validating a novel thermal analysis technique for refractory materials. Commercial ZrC_(0.96) powder was densified by spark plasma sintering to > 96% relative density after 6-30 min at 2173-2453 K under 40-100 MPa. Sintered ceramics were heated to >4000K via pulsed laser heating. Mean values for solidus and liquidus transitions were 3451 and 3608 K, respectively, in fair agreement with the present phase diagram. Post-melting analysis revealed dendritic microstructure and composition consistent with single-phase ZrC. Subsurface gas porosity and ZrC-C eutectic indicate complex processes occurring during melting and freezing.