自润滑功能稀土氧硫化物的原位形成
(1. 中南大学 粉末冶金国家重点实验室，长沙 410083；
2. 长沙矿冶研究院，长沙 410012)
摘 要: 考察了高活性混合稀土(RE)掺杂的WC-8%Co-0.07%RE(质量分数)硬质合金刀片对铸铁的切削试验。采用扫描电镜、能谱分析以及X射线衍射等分析方法对硬质合金烧结体表面、切削试验后刀片的前刀面、后刀面以及切削刃进行观察与分析。结果表明，在稀土硬质合金刀片切削过程中发生了La、Ce从合金内部至刀片工作表面的非同步迁移现象，在刀具工作表面原位形成了具有自润滑功能的稀土氧硫化物。在实验观察与分析基础上，对La、Ce的定向迁移机制与稀土氧硫化物的形成机制进行了探讨。
关键字: 硬质合金；稀土；切削；非同步迁移；自润滑
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Changsha Mining and Metallurgy Research Institute, Changsha 410012, China）
Abstract: As-sintered high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.07%RE (mass fraction) cemented carbide inserts were tested for the turning of cast iron. The sinter skin, flank face, rake face and cutting edge of the inserts after testing were observed and analyzed by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry. Asynchronous migration phenomenon of lanthanum and cerium from the inside to the working faces of the as-sintered insert during the turning process was observed. The results show that a rare earth oxysulfide phase with self lubricating function forms in-situ on the working faces of cemented carbide cutting tool. The mechanisms for the directional migration and formation of rare earth oxysulfide were discussed.
Key words: cemented carbide; rare earth; cutting; asynchronous migration; self lubricating
