超细晶粒硬质合金复合粉的成形特征

Compaction Behavior of Hard Alloy Powders with Ultra-fine Grains

采用沉降分离 ,高能剪切粉碎 ,比表面分析 (BET)和扫描电镜 (SEM)观察等手段研究了超细硬质合金粉末中的桥接团粒在分离 ,破碎过程中 ,松装密度和比表面的变化 ,研究和对比了常规湿磨、高速搅拌球磨、高速剪切粉碎对粉末成形致密化曲线的影响。结果表明 :桥接团粒可被高速剪切粉碎机有效地粉碎。粉末的松装密度成倍地增长 ,并且压坯的相对密度由 33 .5 %增加到 6 0 %

The specific surface area and green density of ultrafine cemented carbide powders (containing bridged particles) were studied before and after sedimentation separating and high energy shear milling by means of BET specific surface area analyzer and SEM. The effects of wet milling, high speed attrition grinding and high energy shear milling on powder compressibility curves were also studied. Results show that bridged particles can be effectively crushed by high energy shear milling. After the crushing of bridged particles, the specific surface area changed little, but the apparent density doubly increased. Meanwhile the relative density of the compact increased from 33.5% to 60%.