跑合过程引发钛合金水基润滑的超低摩擦特性

Super Low Friction Characteristics Initiated by Running-in Process in Water-based Lubricant for Ti-Alloy

以Ti6Al4V盘和Si_(3)N_(4)球为摩擦副、以魔芋葡甘聚糖溶液为润滑剂,使用多功能摩擦磨损试验机对比分析在干摩擦跑合和硼酸跑合条件下钛合金魔芋葡甘聚糖溶液水基润滑的摩擦特性,研究了跑合过程对钛合金水基润滑特性的影响。结果表明:在跑合过程中Si_(3)N_(4)球上形成的磨损区域是实现超低摩擦的关键,两种方式跑合后使用魔芋葡甘聚糖溶液润滑均可达到摩擦系数小于0.01的超低摩擦状态。干摩擦跑合后魔芋葡甘聚糖溶液的浓度较高,且在试验转速较高的条件下较强的流体动压效应可实现超低摩擦。硼酸跑合降低了摩擦副表面的粗糙度,且硼酸离子与魔芋葡甘聚糖分子中的羟基发生化学反应生成更加稳定的水合分子层,在魔芋葡甘聚糖溶液浓度较低的条件下依靠水合分子间的斥力仍可实现超低摩擦。

The influence of running-in process on friction characteristics of Ti-alloy by water-based lubrication process were investigated via CETR universal micro-tribometer(UMT-2) with Ti6 Al4 V disc and Si3N4 ball as tribo-pairs, konjac glucomannan(KGM) solutions as lubricant. The differences of the lubricating properties for Ti-alloy after dry friction and boric acid running-in process were analyzed. The results show that the wear area on the Si_(3)N_(4) ball generated in the running-in process is the key factor that influenced the achieving of super-low friction. The super-low friction state(friction coefficient less than0.01) could be acquired with KGM solution after both boric acid running-in and dry running-in. In the case of dry friction running-in, the super-low friction coefficient can be acquired only for the case with higher concentration KGM solutions and higher running speed, which mainly rely on the stronger hydrodynamic effect. In the case of boric acid running-in, the surface roughness of the tribo-pairs were greatly reduced,and the hydration layer of KGM was promoted by the chemical reactions between the boric acid and the KGM molecules. The super-low friction state could be achieved by the repulsive force between the hydrated KGM layers even for the solutions with low concentration of KGM.