直接碳化技术制备碳化钨粉的研究

Study on WC Powder Prepared by Direct Carbonization Process

本文以两种不同形貌的氧化钨和炭黑为原料,采用加酒精湿磨配炭制取混合料,再经干燥,在中频电炉中,于1 000℃、1 250℃、1 400℃直接碳化,分析碳化产物的相成份、形貌、粒度、炭含量、氧含量。研究发现,不同原料在相同温度直接碳化,碳化产物形貌完全不同;薄片状氧化钨所制得的碳化钨在低倍扫描电镜下观察几乎没有超过50μm的团聚颗粒;在高倍扫描电镜下观察是许多小颗粒的团聚体,并且聚集得很紧密。针状氧化钨原料制得的碳化钨在低倍扫描电镜下观察团粒较多,而且保持着原APT的伪晶形貌,在高倍扫描电镜下观察呈松散的细颗粒聚集体。当直接碳化温度达到1 250℃,反应基本完全,化合碳接近碳化钨理论含碳量。碳化钨粒度随温度的升高而增大。

The mixture powder was prepared by wet grinding two types of tungsten oxide with different morphology, carbon black and alcohol, followed by drying and direct carbonizing in intermediate frequency electric furnace. The selected reaction temperature was 1 000 ℃, 1 250 ℃ and 1 400 ℃. Then the phase composition, morphology, particle size, carbon content and oxygen content of the product were analyzed. It is shown that the products carbonized directly by different raw materials at same temperature have completely different morphologies, few agglomerated granules with a particle size of more than 50 μm in the tungsten carbide powder prepared by lamellar tungsten oxide are observed at low magnification of SEM, while at high magnification the agglomerated granules are observed of some small particles which aggregate very tightly. The tungsten carbide prepared by acerate tungsten oxide has much more aggregates, which maintains the original APT crystal morphology, and the morphology observed at high magnification of SEM is loose fine aggregates. When the direct carbonization temperature reaches at 1 250 ℃, the reaction essentially completes, the combined carbon closes to the theory carbon content. The particle size of the tungsten carbide increases with the increasing of the direct carbonization temoerature.