In situ fabrication of ZrC powder obtained by self-propagating high-temperature synthesis from Al–Zr–C elemental powders

The in situ synthesis of ZrC powder utilizing self-propagating high-temperature synthesis (SHS) reaction that occurred in the compact consisting of Al, Zr and C powders was investigated. The result shows when Al contents were 0–40 wt.% SHS reaction proceeded favorably. The as-products display a uniform distribution of ZrC particles with the sizes ranging from 8 μm at Al free to 50 nm at 40 wt.% Al. The temperature curve, coupled with the quenched treatment, indicates that the Al–Zr reaction to form ZrAl3 initiated and then C reacted with ZrAl3 to form the more stable ZrC phase. It also proves that the mechanism of reaction–precipitation should be responsible for the formation of ZrC in this system. Al has been playing an important role in determining the formation of ZrC, not only as a diluent to inhibit the ZrC grains from coarsening, but also as an intermediate reactant to participate in the total reaction.

Research Highlights
► We synthesized ZrC powder utilizing SHS reaction in the Al-Zr-C system and investigated the microstructure and formation path of ZrC.
► Increasing Al contents, the formed ZrC particles become more refined.
► It provides a novel method to synthesize nano-scaled ZrC particles.
► Al plays an important role in controlling the ZrC-forming reaction during SHS process.