VAPOR GROWTH OF MICRO-COILED CERAMIC FIBERS AND THEIR PROPERTIES

Micro-coiled fibers of carbon, SiC, Si3N4, TiC, ZrC and HfC were prepa red by a metal-impurity activated chemical Vapor deposition or vapour phase metallizing of the coiled carbon fibers. The growth conditions, morphology, growth mechanism and some properties were examined. The do uble-coiled carbon fibers were prepared using acetylene as a carbon so urce and various powders or plates of transition metals, metal carbide s, MoS2, Ti2O3 and Ni single crystal plate as a catalyst at 650-850 de grees C. The triple-coiled SiC fibers were prepared using coked rice h usks and/or SiO as a Si-source and Ni, Cr or Fe as a catalyst at 1400- 1500 degrees C. The double-coiled TiC fibers were prepared by the PCl3 activated CVD process on a graphite substrate using a Pt+Si or Pd+Si mixed catalyst at 1050-1250 degrees C.