AN EXAMINATION OF THE GROWTH MODELS FOR TiC WHISKERS MADE BY CVD

ABSTRACT

Whiskers of refractory compounds such as carbides, nitrides and oxides have been grown by many researchers by chemical vapor deposition. The growth of whiskers from the vapor phase has been suggested to occur by the vapor-solid (VS) and/or the vapor-liquid-solid (VLS) mechanisms. In the growth of TiC whiskers with nickel as the catalyst, the VLS mechanism is widely accepted as the primary initial growth mechanism in which a ternary eutectic of Ni, Ti and C is considered to provide the growth path for the whiskers. In this paper, we examine the published literature on the growth of TiC whiskers by several researchers and show that this view of the ternary eutectic may not explain the whisker growth at temperatures below the eutectic point of the Ti-Ni-C system. This paper attempts to formalize a VLS mechanism model based on a binary eutectic for the observed formation of whiskers at lower temperatures,