Ti粉活化对碳热还原氮化法制备Ti(C,N)粉末的影响

Effect of Ti powder activation on preparation of Ti(C,N) powder by carbothermal reduction and nitridation

以TiO_(2)、碳黑为原料,抛尾Ti粉为活化剂,结合TG/DSC、XRD分析手段,研究抛尾Ti粉活化碳热还原氮化制备Ti(C,N)粉末的动力学和物相演变。采用Kissinger-Akahira-Sunose(KAS)方法计算未添加和添加抛尾Ti粉体系中Ti_(3)O_(5)转变为Ti(C,N)的活化能,分别为(5053.34±683.64)kJ/mol和(4485.46±687.33)kJ/mol,发现抛尾Ti粉可有效降低碳热还原氮化反应的活化能;碳热还原氮化过程的物相演变研究表明,800℃下Ti与TiO_(2)反应直接生成Ti_(4)O_(7),越过了传统未添加钛粉体系中的Ti_(n)O_(2n−1)(n>4)系列中间相转变过程,1400℃保温0.5 h即可得单相Ti(C,N)。在1750℃保温4 h成功制备了w(O)为0.34%、w(游离C)为0.33%,粒径1~2μm的高品质Ti(C,N)粉末。

The kinetics and phase evolution of Ti(C,N)formation process by-carbothermal reduction and nitridation of titania(TiO_(2)),carbon and tailing Ti powder as activator were investigated using TG/DSC,XRD.The Kissinger–Akahira–Sunose(KAS)method was used to calculate the activation energies that Ti_(3)O_(5) reacted to form Ti(C,N)in the system without adding and adding tailing Ti powder,which were(5053.34±683.64)kJ/mol and(4485.46±687.33)kJ/mol respectively.The result indicated that tailing Ti could effectively reduce the activation energy of the carbothermal reduction and nitridation reaction;the phase evolution study of the process showed that Ti reacted with TiO_(2) to form Ti_(4)O_(7) at 800℃,which directly surpassed the Ti_(n)O_(2n−1)(n>4),a series of intermediate phase transformation process,single-phase Ti(C,N)could be obtained by holding at 1400℃for 0.5 h;Finally,the oxygen content of 0.34%,the free carbon content of 0.33%and high-quality Ti(C,N)powder with a particle size of 1−2μm was prepared at 1750℃for 4 h.