Chemical vapour growth of HfC whiskers and their morphology

Abstract

HfC whiskers were prepared from a gas mixture of HfCl₄ + CH₄ + H₂ + Ar in the presence of metal impurities, and the growth conditions and morphology were examined. The HfC whiskers preferentially grew at an H/Cl ratio of above 8, an HfCl₄ gas flow rate of 10–20 standard cm³ min⁻¹, a CH₄ flow rate of 10–20 standard cm³ min⁻¹, and at temperatures above 1050 °C. HfC whiskers, 60–170 μm long, with a ball-like tip and periodically varying diameters, were obtained at 1250 °C using a cobalt impurity.