碳热还原氮化一步法制备钒氮合金工艺研究

对V2O5自还原氮化过程进行热力学分析,并以工业级V2O5和炭黑为原料,经过混料、研磨、压制成块后进行烧结和还原氮化,制得含氮量较高的钒氮合金。结果表明,为了避免V2O5在还原过程中挥发,预还原温度应控制在V2O5熔点(678℃)以下;经过650℃预还原4h,试样中的V2O5才能全部转化为低价态的钒氧化物;V2O5在N2气氛下自还原时,还原终温低于1 271℃时,还原产物优先生成VN,还原终温高于1 271℃时,还原产物中才会出现大量VC;为保证还原产物的高氮和低碳含量,应将还原氮化最终温度控制在1 200～1 300℃。

One-step method of carbon thermal reduction and nitridation to produce vanadium nitrogen alloy

The self-reduction nitridation process of V2O5 was thermodynamically analyzed.V2O5 of industrial grade and carbon black were used as raw materials to prepare briquetting samples through mixing,grinding and pressing,which were further sintered,reduced and nitrated to produce vanadium nitrogen alloy with high nitrogen content.The results show that:(1) In order to avoid V2O5 volatilization loss during reduction,the briquetting samples should be pre-reduced for 4 hours below the melting point 678 ℃ of V2O5,which can transform V2O5 into low valence vanadium oxide;(2) During the self-reduction of V2O5 under N2 atmosphere,if the final reduction temperature is below 1 271 ℃,VN is preferentially formed;if larger than 1 271 ℃,a huge amount of VC is found in the reduced product;(3) To ensure high nitrogen and low carbon contents of the reduced products,the final reduction and nitridation temperature should be set at 1 200~1 300 ℃.