This paper is devoted to investigate the friction-reducing and wear protection performance of TiO₂ nanoparticles as lubricant additive in fully formulated engine oil. The phase of TiO₂ nanoparticles, synthesized by a sol–gel process, was characterized by XRD. A four-ball tribometer was used to compare the friction coefficient and wear when lubricated by engine oil in absence and presence of TiO₂ nanoparticles. The surface chemistry of tribofilm was observed by XPS. The experiments showed that phase of TiO₂ nanoparticles plays great role in determining the friction-reducing and wear protection of engine oil containing TiO₂ nanoparticles. TiO₂ nanoparticles upon calcination at 300 °C are amorphous, showing lowest hardness and then best friction-reducing and wear protection performance in engine oil. Rutile nanoparticles obtained upon calcination at the temperature above 700 °C, on the contrary, act as abrasive in the sliding contact and present larger wear than the blank engine oil.

本文致力于研究TiO ₂纳米颗粒作为润滑油添加剂在全配方机油中的减摩和耐磨性能。XRD表征了通过溶胶-凝胶法合成的TiO ₂纳米粒子的相。使用四球摩擦计比较在不存在和存在TiO ₂纳米粒子的情况下用机油润滑时的摩擦系数和磨损。用XPS观察摩擦膜的表面化学。实验表明，TiO ₂纳米颗粒的相在决定含TiO ₂纳米颗粒的发动机油的减摩和磨损保护方面起着重要作用。二氧化钛₂在300°C下煅烧的纳米颗粒是无定形的，在发动机油中显示出最低的硬度，然后具有最佳的减摩和抗磨损性能。相反，在高于700°C的温度下煅烧获得的金红石纳米颗粒在滑动接触中起磨料作用，并且比空白机油具有更大的磨损。