WC在湿磨中的分散与破碎过程研究

Research on Dispersion and Breaking Process during Wet Milling of WC

本文在球料比一定的情况下,分别对不同粒度规格的WC进行湿式球磨,并在不同球磨时间取样进行测试。通过氮吸附比表面法、激光粒度分布仪、XRD及SEM电镜等手段,对不同球磨时间下的WC的粒度及粒度分布、晶粒尺寸及破碎过程中粉体的形貌进行分析测试。结果表明:细晶颗粒WC和中粗颗粒WC随球磨时间延长,虽然平均粒度都在细化,但是其细化机理却是不同的。细颗粒WC破碎主要表现为"软团聚"团粒的分散,并且在短时间球磨就能将其分散开,WC颗粒本身并无明显的破碎过程;而中粗颗粒WC主要表现为"硬团聚"体及多晶颗粒随着球磨时间的延长而破碎,并且在球磨达到一定强度后,部分粗大WC晶粒表面也会出现裂纹,进而引起WC晶粒的破碎。

Wet milling of WC powder with different particle size was carried out under a certain ball to powder weight ratio, and samples were taken at different time during milling. The particle size and particle size distribution, crystal size and morphologies of the samples were analyzed by means of nitrogen adsorption BET surface area analyzer, laser particle analyzer, X-ray diffractometer and scanning electron microscope. The results show that the average particle sizes of fine WC powder, middle WC powder and coarse WC powder are all reduced with the increase of milling time, but their refinement mechanism are different. The breaking process of fine WC particles presents as the dispersion of soft aggregations, so a short time ball milling can make the particles completely disperse, and no obvious breaking of WC crystals appears. However, the breaking process of middle WC particles and coarse WC particles presents as the breaking of hard aggregations and polycrystal particles with the extension of ball milling time, cracks appear on the surface of parts of coarse WC crystals, and then the breaking of the WC crystals occurs.