Mechanism for the formation of SiC by carbothermal reduction reaction using a microwave heating technique

Abstract

A pure phase of SiC was formed by microwave heating (2.45 GHz) a powder mixture consisting of SiO₂:carbon black in a 1:3 molar ratio at 1300°C for 0.5 h in a nitrogen atmosphere. In contrast, when the same powder mixture was heated at 1700°C for 0.5 h in a nitrogen atmosphere using a conventional electric furnace, low crystallinity SiC was formed with carbon black remaining as an impurity. The mechanism for the formation of SiC from a powder mixture of SiO₂ and carbon using microwave heating is discussed on the basis of chemical thermodynamics, and compared to that for conventional heating with a carbothermal reduction reaction. As a result, the advantage of carbothermal reduction reaction by microwave heating was confirmed.