水溶性LaF_3纳米颗粒的制备及其摩擦学行为研究

Preparation of Water-soluble LaF_3 Nanoparticles and Study on Its Tribological Properties

以柠檬酸为修饰剂在水溶液中合成表面修饰LaF3纳米微粒,通过X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、热重分析(TG-DTA)、激光粒度分布仪、透射电子显微镜(TEM)、X射线光电子能谱仪(XPS)等测试手段对其结构和形貌进行表征;采用四球摩擦磨损试验机考察LaF3纳米微粒作为添加剂时的摩擦学行为;采用X射线光电子能谱仪(XPS)分析钢球磨损表面的元素组成。结果表明,柠檬酸修饰的LaF3纳米微粒,平均粒径约为4 nm;LaF3纳米微粒在水中的分散性良好,作为水基添加剂,在摩擦过程中可在钢摩擦副表面的形成由Fe2O3、La2O3等为主要组成部分的边界润滑膜,因此表现出极好的抗磨减摩性能,具有很好的应用前景。

The water-soluble LaF3 nanoparticles modified by citric acid were synthesized. Their morphology and structure were characterized by X-ray diffraction （ XRD ）, Fourier transform infrared spectroscopy （ FTIR ）, thermal analysis （ TG- DTA）, laser granulometry, transmission electron microscope（ TEM ）, and X-ray photoelectron spectroscopy（ XPS ）. The tri- bological behaviors of water soluble LaF3 nanoparticles as additives in water were evaluated with a four-ball tribometer, and the elemental composition of the wear scar on steel ball surface was analyzed by X-ray photoelectron spectroscopy（XPS）. The results show that the LaF3 nanoparticles, with a diameter about 4 nm and modified by a citric acid, can be well dispers- ed in water. As the water-based lubricant additive, a boundary film mainly composed of Fe203 ,La203 on the rubbed surface could be formed. Therefore, LaF3 nanoparticles have the best friction reducing and antiwear behaviors, showing promising usage potential.