直接还原碳化法制备超细WC粉体研究

Preparation of Ultrafine WC Powders by Direct Reduction and Carbonization Process

采用直接还原碳化法,以偏钨酸铵(AMT)和炭黑为原材料,在N2气氛中制备出超细WC粉末。对不同温度下反应产物进行XRD、SEM以及化学成分分析,结果显示:含钨相逐步由AMT向WO3,WO2.72,W,W2C转变并最终生成完全渗碳的WC粉末;1 150℃下反应2 h可得到化合碳含量为6.09%的超细WC粉末,粒度为0.3μm,比表面积为2.285 m2/g。对反应过程及机理进行了分析探讨,结果表明:碳化温度应高于981 K,反应产生CO,降低CO分压有利于碳化反应的进行。

Adopting the direct reduction and carbonization method,ultrafine WC powders can be prepared in a N2 atmosphere with carbon black and AMT as raw materials.The XRD,SEM and elemental content analysis on the products obtained under different reaction temperatures show that,with the increase of temperature,the phase of tungsten turned gradually from AMT to WO3,WO2.72,W,W2C and a fully carburized WC powder can be eventually generated.After treated for 2 hrs at 1150 ℃,ultrafine WC powder with a mean size of 0.3 μm,a combined carbon content of 6.09% and a specific surface area（BET method） of 2.285 m2/g,can be synthesized.Investigation on the reaction process and mechanism shows that,the initial carbonization temperature should exceed 981 K,as,under this condition,the gas production of the reaction was mainly CO,and it is conducive to the carbonization progress to reduce the partial pressure of CO in the system.