Preparation and characterization of ZrB2–SiC composite powders from zircon via microwave-assisted boro/carbothermal reduction

• Published in: Ceramics international Vol. 41; no. 10; pp. 14419 - 14426
• Main Authors: Deng, Xiangong, Du, Shuang, Zhang, Haijun, Li, Faliang, Wang, Junkai, Zhao, Wanguo, Liang, Feng, Huang, Zhong, Zhang, Shaowei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2015
• Subjects: Boro/carbothermal reduction; Composite powders; Microwave; Zircon; ZrB2–SiC; Microwave; Boro/carbothermal reduction; ZrB2–SiC; Composite powders; Zircon
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2015.07.077

ZrB2–SiC composite powders were successfully synthesized via microwave-assisted boro/carbothermal reduction technique using zircon (ZrSiO4), activated carbon (C) and boron oxide (B2O3) as raw materials. They were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). Thermodynamic analysis on the synthesis process was carried out, and the effects of SiC bedding powder, reaction temperature, soaking time and n(B2O3):n(ZrSiO4) molar ratio on the formation of ZrB2–SiC composite powders were examined. The results showed that phase pure ZrB2–SiC composite powders were successfully synthesized at 1573K which was 200K lower than that required by using the conventional boro/carbothermal reduction method. In the final composite powders, fibrous SiC phases with 0.1–0.5μm in diameter and 1.4–4.2μm in length were homogeneously distributed among spherical ZrB2 particles with the average size of 0.1–1μm.