Phase Transformation of MgAlON-SiAlON Powders Synthesized by Carbothermal Reduction-Nitridation from Ludwigite Tailings

Abstract:

This paper focuses on the influence of temperature and holding time on synthesizing MgAlON-SiAlON powders applying CRN method. The results were analyzed by chemical and XRD analysis technology. The experimental results revealed that β-SiAlON, as an intermediate phase, appeared in the synthesized products at 1200°C. With the increase of synthesis temperature, β-SiAlON was translated into Mg-SiAlON polytypoid (Mg_1.25Si_1.25Al_2.5O₃N₃) and reached the maximum at 1450°C. Increasing synthesis temperature was beneficial to generate MgAlON, and the optimal condition of temperature for powders synthesis was 1500°C. β-SiAlON disappeared with the increase of holding time. MgAlON and Mg-SiAlON polytypoid became the main crystalline phases with a holding time of 4h. Whats more, the phase compositions had no evident change with longer holding time. Flaky MgAlON grains and elongated Mg-SiAlON grains were observed in synthesized powders.

• Periodical: Applied Mechanics and Materials (Volumes 365-366)
• Pages: 1095-1099
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.365-366.1095
• Online since: August 2013
• Authors: Tao Jiang, Lu Zhang, Yi Tang, Yi Xia, Xiang Xin Xue
• Keywords: Carbothermal Reduction-Nitridation, Ludwigite Tailings, MgAlON-SiAlON, Powders

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