Fabrication of silicon carbide whiskers and whisker-containing composite coatings without using a metallic catalyst

Abstract

Silicon carbide has been focused on by many researchers because of its outstanding mechanical and chemical properties. Silicon carbide whiskers are important for the reinforcement of ceramic matrix composites. However, metallic catalysts, which are necessary for the growth of whiskers, can cause degradation of their properties. Thus, we have made silicon carbide whiskers without using the metallic catalyst. Whiskers were obtained with an input gas ratio of above 20, and their diameter decreased as the input gas ratio increased. As the input gas ratio [H 2(+N 2)/MTS] increases, a transition from whisker growth to film growth occurred at a higher pressure. We also deposited whisker-containing coatings based on the above conditions by alternating the whisker growth and the matrix filling process. The coatings showed pebble-like structures, and their morphologies differed according to the growth condition of the whiskers in the coating layer.