Thermal explosion synthesis of ZrC particles and their mechanism of formation from Al–Zr–C elemental powders

ZrC particles were fabricated by thermal explosion (TE) from mixture of Al, Zr and C elemental powders. Without the addition of Al, the synthesized ZrC particles had irregular shape of ~ 4.0 μm in average. Increasing Al content up to 30 wt.%, however, refined significantly them down to < 0.2 μm with regularly square morphology. The Al effect of reaction mechanism promoted the ZrC formation as diluents in the course of TE, which was clarified using differential thermal analysis and X-ray diffraction technique. The melting of Al favored the reaction with Zr to generate ZrAl3, and then the dissolution of C into the Al–Zr liquid resulted in precipitation of ZrC. Meanwhile, the exothermic effect prompted C atoms dissolving into Zr–Al liquid and eventually led to precipitation of ZrC out of the supersaturated liquid. The Al addition inhibited particle growth, but also promoted the TE reaction.

► ZrC particles were prepared by TE from Al–Zr–C system. ► The formation mechanism of ZrC particles was discussed. ► The synthesized ZrC particles were determined to be ultra-fine or nano-scale with Al addition. ► Al not only prevents the synthesized products from growing but also promotes the TE reaction.