氮化钒制备热力学和动力学

Thermodynamics and Dynamics of Vanadium Nitride Preparation

研究了氮气气氛下V_2O_5碳热还原氮化反应的热力学和动力学,并进行了实验验证.结果表明,反应炉内V_2O_5优先还原,在碳充足的情况下,还原的中间产物依次是V2O3,VO,V2C,VC.还原氮化通常在N2气氛下同炉进行,先还原后氮化,温度高于1267℃时,VC比VN更稳定,存在动力学和热力学矛盾.V_2O_5碳热还原反应的控速环节为球形颗粒的三维扩散,氮化反应的控速环节为一级界面反应.制备了氮含量18%、钒含量78%、碳含量小于2%的钒氮合金.

The thermodynamics and dynamics of the reduction and nitridation of V2O5 at N2 atmosphere were researched with the experimental verification. The results indicated that the prior reaction is V2O5 reduction in the furnace, and the semifinished products are sequentially by V2O3, VO, V2C and VC when the carbon is sufficient. Reduction and nitridation are currently carried out in one furnace at N2 atmosphere. Reduction is prior to nitridation. The stability of VC is better than VN when the temperature is over 1267 ~C, and heterogeneity exits at thermodynamic and pure dynamic. The restriction of carbon thermal reduction of VzO5 is three-dimensional diffusion in spherical particle, while the restriction of nitridation is primary interface reaction. The vanadium nitride of 18% nitrogen and 78% vanadium content is obtained by the experiment, while the carbon is less 2%.