疏水性纳米TiO2制备及其在菜籽油中的摩擦磨损性能

以纳米TiO2为原料、硬脂酸为表面改性剂,通过超声反应制备了疏水性纳米TiO2（SA-TiO2）;采用扫描电子显微镜（SEM）、红外光谱仪及接触角测量仪对其微结构进行了表征。以SA-TiO2为润滑油添加剂,在四球试验机上考察了其在菜籽油中的摩擦磨损性能,并利用SEM观察钢球表面磨斑形貌,用能谱仪（EDS）和X射线光电子能谱仪（XPS）分析了钢球表面磨斑的化学成分。结果表明：SA-TiO2为疏水性单分散球状颗粒,其平均直径约为20 nm;SA-TiO2能够提高菜籽油的抗磨减摩性能,当SA-TiO2的质量分数为1%,菜籽油的抗磨减摩性能达到最佳;钢球表面磨斑的EDS和XPS分析表明,纳米微粒在钢球摩擦表面形成了一层含菜籽油和SA-TiO2的吸附膜,在摩擦剪切作用下,发生摩擦化学反应生成了一层含钛、铁氧化物的边界润滑膜,这种边界润滑膜起到了良好的润滑作用。

Preparation,Friction and Wear Properties of Hydrophobic TiO_2 Nanoparticles in Rapeseed Oil

Hydrophobic titanium dioxide composite nanoparticles,abbreviated as SA-TiO2,were prepared via ultrasonic reaction method with TiO2nanoparticles as stock and SA as surface modifier. The microstructure of as prepared SA-TiO2was characterized by means of scanning electron microscope, Fourier transform infrared spectrometry and contact angle metrical instrument. Moreover,the friction and wear properties of SA-TiO2as lubricant additives in rapeseed oil were evaluated with a four-ball friction and wear tester. The morphology as well as elemental composition and chemical characteristics of worn steel surfaces were investigated by scanning electron microscope,energy dispersive X-ray spectrometer and X-ray photoelectron spectroscope. Results showed that as-prepared SA-TiO2particles displayed monodisperse spheres morphology with an average size of about 20 nm,and the measurement of contact angle indicated that SA-TiO2was hydrophobic. In the meantime, SA-TiO2could improve the anti-wear and friction-reducing capacities of rapeseed oil. The optimal anti-wear and friction-reducing abilities were obtained at an SA-TiO2content of 1%. EDS and XPS analysis of worn steel surfaces indicated that an absorption film containing rapeseed oil and SA-TiO2was formed on the rubbing surfaces,and then a boundary lubrication film mainly composed of the oxides of iron and titanium was formed via tribological chemical reaction,which provided the rapeseed oil with good lubricating properties.