Journal of Inorganic Materials

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Controllable Synthesis of High-purity β-SiAlON Powder

YUE Chang-Sheng1, GUO Ming1, ZHANG Mei1, WANG Xi-Dong2, ZHANG Zhi-An3, PENG Ben1   

  1. (1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. College of Engineering, Peking University, Beijing 100871, China; 3 Shanxi Xinxing Kiln & Furnace Group Limited Company, Taiyuan 030003, China)
  • Received:2009-03-11 Revised:2009-04-13 Published:2009-11-20 Online:2010-04-22

Abstract: The Gibbs free values of different SiAlON were assessed by the thermodynamic quasi-paraboloid rule in Si3N4-AlN-SiO2-Al2O3 system and the thermodynamic parameter for β-SiAlON were explored at 1800K. The synthesis of β-SiAlON based on coal gangue and carbon black by carbonthermal reduction nitridation method, and phase transformation of β-SiAlON powder in various atmospheres (such as air or nitrogen of different purity) were discussed in detail. Thermodynamic analysis reveals that different SiAlON can be synthesized in suitable atmosphere parameter Y(Y=lg(PO2/Pθ)-2/3lg(PN2/Pθ) at 1800K, and low Y value is beneficial to synthesis of βSiAlON. When excessive carbon exists in the atmosphere, with the increase of purity (α) of initial nitrogen, the Y value decreases, and the relationship between purity(α) and Y value is Y=2lg[(2-2α)/(2-α)]-2/3lg[α/(2-α)]-15.616. The experiment results shows that the suitable initial parameters based on thermodynamic analysis is highly advantageous in controllable synthesis of high-purity β-SiAlON, the proper initial parameters is that samples, burying in coke, are sintered at 1800K in a flowing nitrogen atmosphere, the purity range of nitrogen is about 0.995-0.999.

Key words: β-SiAlON, thermodynamic, controllable synthesis

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