Abstract

The tribological performance of polymer-stabilized TiO₂ particles dispersed in mineral base oil was investigated. Two polymer–TiO₂ mass ratios were investigated, with a constant polymer concentration of 0.3 wt% and two nanoparticle concentrations of 0.1 and 1 wt%. Friction tests were carried out with a pin-on–reciprocating flat test configuration under boundary-lubricated sliding conditions in the presence of a steel–steel contact and at two temperatures (20 and 100 °C). The results show the very good antiwear performance of the nanoparticle-based dispersions. The most promising results were obtained with 0.1 wt% TiO₂ particles and at 20 °C. At this temperature, the wear resistance properties of the TiO₂ particles surpass those of zinc dialkyldithiophosphate (ZDDP). The tribofilms generated during the friction tests were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), and X-ray photoelectron spectroscopy (XPS). A tribofilm composed of agglomerates of TiO₂ particles embedded in a matrix formed by the polymer was observed. The combination of the polymer used as a dispersant and the TiO₂ particles allows good tribological performance that was observed during the friction tests. The formulation including TiO₂ particles could improve the antiwear properties of materials in an environment where conventional wear reducing additives do not form tribofilms due to low temperatures.

摘要

研究了分散在矿物基础油中的聚合物稳定的TiO ₂颗粒的摩擦学性能。研究了两种聚合物-TiO _2的质量比，恒定的聚合物浓度为0.3 wt％，两个纳米颗粒的浓度为0.1和1 wt％。在钢与钢接触的情况下，在两个温度（20和100°C）下，在边界润滑的滑动条件下，采用销钉往复式平面测试结构进行了摩擦测试。结果显示了基于纳米颗粒的分散体非常好的抗磨性能。在20°C下使用0.1 wt％的TiO ₂颗粒可获得最有希望的结果。在此温度下，TiO ₂的耐磨性颗粒超过二烷基二硫代磷酸锌（ZDDP）的颗粒。使用扫描电子显微镜（SEM），透射电子显微镜（TEM）结合能量色散X射线光谱仪（EDS）和电子能量损失光谱仪（EELS）以及X射线光电子光谱仪对在摩擦测试过程中产生的摩擦膜进行了表征（XPS）。观察到由TiO ₂颗粒的团聚物包埋在由聚合物形成的基质中的摩擦膜。用作分散剂的聚合物和TiO ₂颗粒的组合可实现良好的摩擦学性能，这在摩擦测试中可观察到。包含TiO ₂的配方 在传统的减磨添加剂由于低温而不会形成摩擦膜的环境中，这些颗粒可以改善材料的抗磨性能。