Preparation and properties of SiC micro-coils by the vapor phase siliconizing of carbon micro-coils

Carbon micro-coils, which have a fiber diameter of submicron size, a coil diameter of 1-10 mu m, and an amorphous structure, can be obtained by the decomposition of acetylene. In this study, SiC micro-coils were prepared by the vapor phase siliconizing of the carbon micro-coils, and the preparation conditions and some properties were examined. The carbon coils were very difficult to siliconize, and the siliconizing velocity at 1530 degrees C was 1/4 that of the commercial carbon fibers and 1/100 that of the graphite plate. The SiC micro-coils have a good oxidation resistance up to 1100 degrees C, while the carbon coils began to be oxidized at about 500 degrees C. The bulk electrical resistivity increased with increasing Si/C ratio and decreased with increasing bulk density. (C) 2000 Elsevier Science Ltd. All rights reserved.