Large-Scale Fabrication of SiC-TiC@C Powders via Modified Molten Salt Shielding Synthesis Technique and Their Effect on the Properties of Al[sub.2]O[sub.3]-MgO Castables

• Published in: Materials Vol. 16; no. 17
• Main Authors: Li, Yong, Yin, Yicheng, Chen, Jing, Kang, Xiaoxu, Kang, Shihao, Ma, Haoxuan, Zhang, Shaowei, Jia, Quanli
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.08.2023
• Subjects: Graphite; Methods; Powders; Silicon carbide
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16175895

Graphite flakes are commonly used to fabricate carbon-based refractories owing to their superior properties, including better corrosion resistance and thermal shock resistance (TSR); unfortunately, their insufficient water-wettability has remarkably hindered their application in castables. Aiming to enhance their water-wettability, a facile and low-cost technique for fabricating carbides coated in graphite was proposed in this work. Firstly, SiC-TiC coated graphite (SiC-TiC@C) powders were prepared via modified molten salt shielding synthesis in an air atmosphere using graphite flake, Si and Ti powders as raw materials and NaCl-KCl as the molten salt shielding medium. Water-wettability and oxidation resistance of SiC-TiC@C powders were significantly improved. Compared to the Al[sub.2]O[sub.3]-MgO castables with graphite flakes, the water demand of the castables with SiC-TiC@C was noticeably decreased from 6.85% to 4.89%, thereby decreasing the apparent porosity of the castables with 5% SiC-TiC@C (from 20.3% to 13%), enhancing the cold strength, hot strength and oxidation resistance of the castables. Such enhancements are ascribed to continuous and crack-free SiC-TiC coatings on graphite surfaces ensuring that the castables have outstanding properties.