Effect of water-vapor content on reaction rate of hexagonal BN powder at 1273K
Hexagonal BN powder with average particle size of 1.2μm was exposed at 1273K in H2O/air gas mixture with the range of mass ratio from 0:100 to 6.5:100 at a total pressure of 1 atm. Thermalgravimetry(TG) method was used to measure the reaction behavior of BN powder in water vapor. XRD and SEM were employed to analyze the phases and morphological revolution during reaction. The TG curves showed that the overall reaction process could be divided into two stages. In first stage, weight gained rapidly and the main reaction was the oxidation of BN. The weight gain turning point of the curves with different water-vapor contents varied, indicating that water-vapor had an impact on oxidation rate to some degree. In second stage, weight loss due to B2O3 reacting with H2O to form volatile product. The rate of weight loss increased with increasing the water vapor content. The reaction rate was described by a linear rate law, i.e., α = - klt. The relationship between kl and partial pressure of water vapor p was described by a function of kl = 0.4p. The determination of the activation energy was complicated due to variations in the reaction mechanism.
Reaction kinetics water-vapor content BN powder
Ziyou YU Xinmei HOU Zhiyuan CHEN Kuo-Chih CHOU
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing100083, China Department of Physical Chemistry, School of Metallurgical and Ecological Engineering, University of Science& Technology Beijing, Beijing 100083, China
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-9
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）