VC的氮化反应热力学与动力学分析及其实验验证

摘要

The stability of VC in N2 containing atmosphere is an important issue in the preparation of ultrafine WC containing vanadium.The results of thermodynamics and thermogravimetric analysis show that the nitridation of VC will proceed under N2 containing atmosphere in the temperature range of 245～1 272 ℃ and a reverse transformation of nitride products will occur when the temperature exceeds 1 272 ℃.Based on the analysis of thermogravimetric curves,it can be concluded that the nitridation reaction of VC powder is in accordance with the reaction control mechanism and the relationship between the nitridation reaction rate of VC and temperature is established.The experimental results show that the nitridation reaction of VC at 1 050 ℃ becomes stable after 2 h nitridation,and the compositions of the nitrided products of the original VC and 2 h attritor milling activated VC are V(C0.68,N0.32) and V(C0.54,N0.46),respectively.%VC在含N2气氛中的稳定性是含V超细WC制备工艺制订应该关注的一个重要问题.热力学与热重分析结果表明,在245～1 272℃温度范围内,在含N2气氛中,VC会发生氮化反应;超过1 272℃后,在含C环境中,会发生VC氮化产物的脱氮和碳化反应.基于对热重分析曲线的解析,确定VC的氮化反应属于反应控制机制;在此基础上,建立了VC氮化反应速率与温度的关系方程.实验验证结果表明:在1 050℃氮化2h后,VC粉末的氮化反应已趋稳定,原生态和2h搅拌球磨活化态VC粉末氮化产物的化学式分别为V(C0.68,N0.32)和V(C0.54,N0.46).