高能球磨时间对碳质中间相结构及其高温摩擦磨损特性的影响

Effect of Ball Milling Time on Structure and High Temperature Friction and Wear Behavior of Carbonaceous Mesophases

采用高能球磨法对煤焦油沥青碳质中间相进行非平衡处理,利用X射线衍射仪和激光Raman光谱仪研究中间相高能球磨前后的结构变化,用差示扫描量热仪测试不同状态下碳质中间相的结构稳定性,在SRV高温摩擦磨损试验机上采用阶梯升温方式考察了碳质中间相作为润滑油添加剂的摩擦磨损性能.结果表明,高能球磨处理导致中间相的结晶有序度下降,微晶石墨平面尺寸减小,层间间距增加,说明高能球磨处理促使中间相向无定形结构转变.高能球磨时间越长,中间相的无定形结构特征越明显.高能球磨处理降低了碳质中间相的稳定性,随着球磨时间增加,碳质中间相的稳定性变差.球磨态碳质中间相具有高温减摩抗磨效应,球磨时间越长,其减摩抗磨效果越明显.高能球磨处理在一定程度上促进摩擦机械诱发碳质中间相的石墨化转变,从而对其高温减摩抗磨效应有一定促进作用,球磨时间越长,其促进作用越大.

A coal tar pitch-derived carbonaceous mesophase （CM） was treated in a high-energy ball mill apparatus. The structures of the raw and the as-milled CMs were characterized by X ray diffraction and Laser-Raman spectroscopic techniques, the structural stability for the as-milled CMs was measured with a differential scanning calo- rimeter （DSC） , and the friction and wear behavior for the CMs as lubricating additives were investigated in a step heating scheme by using a SRV high temperature friction and wear tester. The results showed that high-energy ball milling led to a drop in the crystallinity of the CMs and a decrease in the size of graphite planar micro-crystals, implying a higher structural amorphism caused by the high energy ball milling. Furthermore, the extended ball milling facilitated the structural amorphous transition for the CMs. In addition, high-energy ball milling resulted in a lower structural stability for the CMs, and the stability further decreased as the ball milling time increased. The as-milled CMs exhibited friction-reducing and wear resistant effect at high temperature, which was strengthened by longer ball milling. High-energy ball millingis supposed to have a beneficial effect for the graphitization of the CMs induced by friction and mechanical interaction, and, therefore, facilitate the high temperature anti-friction and wear resistant effect to some extent. This effect can be enhanced through prolonged ball milling.