Study on the preparation of silicon carbide from carbon in waste cathodes

Abstract

Silicon carbide as the core material for third-generation semiconductors plays an important role in many fields; however, its large-scale applications as well as low-cost synthesis remain a challenge. Silicon carbide was prepared via carbothermal reduction using silicon dioxide and purified waste cathodes as the carbon source. The optimum conditions for preparing silicon carbide using waste cathodes are temperature = 1550 °C, molar ratio of carbon to silicon = 3:1 and holding time = 3 h. The microstructure of the prepared silicon carbide was investigated using x-ray diffraction (XRD), infrared spectroscopy and scanning electron microscopy (SEM). The XRD results of the prepared silicon carbide showed that β-SiC was the main phase of the prepared silicon carbide. The SEM results showed that the prepared silicon carbide was fibrous. The growth mechanism of silicon carbide was proposed using the thermodynamic calculations of chemical reactions.