Reaction Synthesis of Nano-scale ZrC Particulates by Self-propagating High-temperature Synthesis from Al–Zr–C Powder Mixtures

Abstract

Nano-scale ZrC particles were synthesized by self-propagating high-temperature synthesis (SHS) reaction from 30–40 mass% Al–Zr–C powder mixtures. The size of ZrC particles evidently reduced from ~160 nm with a nearly spherical shape in 30 mass% Al to ~60 nm with a tetragonal morphology in 40 mass% Al. The reaction mechanism to form ZrC was discussed by DTA and X-ray diffraction analysis. The results revealed that ZrAl3 metastable phase was initially formed by Al–Zr reaction, and then the formation of nano-scale ZrC grain was controlled by the dissolution of C into a Zr–Al melt and the precipitation from the melt. Al in the compact serves not only as a diluent inhibiting the ZrC particle from coarsening, but also as an intermediate reactant participating in the reaction process.