Powder Technology, Vol.317, 209-215, 2017
Catalytic effect of cobalt on microwave synthesis of beta-SiC powder
beta-SiC was synthesized by a microwave reaction method in Ar, using silicon powder and phenolic resin as raw materials, and cobalt nitrate as a catalyst precursor. The effects of temperature, time, and catalyst content on the formation of SiC were investigated. When 1.0-2.0 wt%Co was used as a catalyst, phase pure beta-SiC was formed after 30 min at 1150 degrees C. This synthesis temperature was 100 degrees C lower than that required by the conventional heating route catalyzed by with the identical amounts of catalyst. When a catalyst was absent, the synthesis temperature of beta-SiC was as high as 1250 degrees C even in the case of using microwave heating. beta-SiC particulates were formed, along with some whisker-shaped beta-SiC of 30-100 nm in diameter and up to 20 mu m in length. Density Functional Theory (DFT) calculations suggest that under the test conditions the formation of Co/Si alloy was energetically favorable, and played an important role in the Si-Si bond breaking and the subsequent SiC formation. (C) 2017 Elsevier B.V. All rights reserved.