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

Abstract

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 >4000 K 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. Postmelting 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.