SHS synthesis of Si-SiC composite powders using Mg and reactants from industrial waste

• Published in: Metals and materials international 2017, 23(6), , pp.1188-1196
• Main Author: Chanadee, Tawat
• Format: Article
• Language: English
• Subjects: Acid leaching; Activated carbon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coal mines; Crystal structure; Crystallinity; Electron microscopy; Engineering Thermodynamics; Fly ash; Heat and Mass Transfer; Intermetallic compounds; Leaching; Machines; Magnesium compounds; Magnesium oxide; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Metallic Materials; Processes; Research Paper; Rubber; Sawdust; Scanning electron microscopy; Self-propagating synthesis; Silicides; Silicon carbide; Silicon dioxide; Solid Mechanics; 재료공학
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-017-7111-0

Si-SiC composite powders were synthesized by self-propagating high-temperature synthesis (SHS) using reactants of fly ash-based silica, sawdust-based activated carbon, and magnesium. Fly ash-based silica and sawdust-based activated carbon were prepared from coal mining fly ash and Para rubber-wood sawdust, respectively. The work investigated the effects of the synthesis atmosphere (air and Ar) on the phase and morphology of the SHS products. The SHS product was leached by a two-step acid leaching processes, to obtain the Si-SiC composite powder. The SHS product and SHS product after leaching were characterized by X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectrometry. The results indicated that the SHS product synthesized in air consisted of Si, SiC, MgO, and intermediate phases (SiO 2 , Mg, Mg 2 SiO 4 , Mg 2 Si), whereas the SHS product synthesized in Ar consisted of Si, SiC, MgO and a little Mg 2 SiO 4 . The SiC content in the leached-SHS product was higher when Ar was used as the synthesis atmosphere. As well as affecting the purity, the synthesis atmospheres also affected the average crystalline sizes of the products. The crystalline size of the product synthesized in Ar was smaller than that of the product synthesized in air. All of the results showed that fly ash and sawdust could be effective waste-material reactants for the synthesis of Si-SiC composite powders.