SYNTHESIS OF A SILICON CARBIDE FROM NATURAL RAW MATERIAL IN A SOLAR FURNACE

Abstract

In this study, the processes involved in synthesis of silicon carbide (SiC) from a natural mineral raw material (diatomite mixed with coke) were investigated. The initial material mixture was placed in a graphite crucible installed on the focal zone of a large solar furnace. High-temperature heating was carried out using a stream of concentrated high-density solar radiation (200-300 W/cm²). After irradiating the material sample with the concentrated solar radiation, the crucible was cooled arbitrarily for 30 minutes. The synthesized material contained three phases: β-SiC with a cubic crystalline lattice and lattice parameter of 0.436 nm; α-SiC with a hexagonal crystalline lattice and lattice parameters of a = 0.307 nm and c = 1.511nm; and graphite with a hexagonal crystalline lattice. The SiC material obtained in the solar furnace in a freshly sintered state showed high refractoriness (up to 1650°C), while the material fired at 1550°C showed refractoriness up to 1580°C.