Catalytic effect of nickel on the growth of zirconium carbide whiskers by chemical vapor deposition

Abstract

The growth of ZrC whiskers from the ZrCl 4-H 2-CH 4 system was investigated on various metals and refractory oxides. Ni was the most effective of the materials examined for the growth of ZrC whiskers. The growth of whiskers on Ni occurred in the temperature range 1200–1400 °C which is similar to that found for growth on a mullite substrate. The morphology and lattice constant of ZrC whiskers deposited on Ni were the same as those on mullite. The whiskers grew preferentially in the [100] direction with square cross sections and side faces of {110}. Growth rates in both the axial and the radial directions were several times larger on Ni than on mullite. The ratio of the growth rate in the radial direction to that in the axial direction was about 1/300. The growth rate in the axial direction varied with both zirconium tetrachloride and methane concentrations. The growth mechanism is discussed.