Preparation and tribological properties of lanthanum-doped TiO2 nanoparticles in rapeseed oil

• Published in: Journal of rare earths Vol. 31; no. 6; pp. 589 - 594
• Main Author: 谷科城 陈波水 陈勇
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2013
• Subjects: lanthanum; lubricant additive; nanoparticle; Oleic acid; preparation; Rapeseed oil; Rare earth metals; rare earths; Scanning electron microscopy; Spectrometry; Spectroscopy; Steels; Titanium dioxide; tribological properties; Tribology; X-rays; 傅里叶变换红外光谱法; 制备; 四球摩擦磨损试验机; 扫描电子显微镜; 掺杂纳米TiO2; 摩擦学性能; 菜籽油; 镧掺杂; lubricant additive; lanthanum; titanium dioxide; nanoparticle; rapeseed oil; tribological properties; preparation; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(12)60325-1

Oleic acid （denoted as OA） surface-capped lanthanum-doped titanium dioxide composite nanoparticles, abbreviated as OA/La-TiO2, were prepared via sol-gel method in association with surface modification by oleic acid. The microstructure of as-prepared OA/La-TiO2 was characterized by means of X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry, and their thermal stability was evaluated by thermogravimetry and differential scanning calorimetry. Moreover, the tribological properties of OA/La-TiO2 as 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 was investigated by scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Results showed that as-prepared OA/La-TiO2 particles were of spherical shape and had an average diameter of 20 nm. In the meantime, OA/La-TiO2 particles doped with 1.5% （molar ratio; the same hereafter） and 2.5% of lanthanum could markedly improve the anti-wear and friction-reducing capacities of rapeseed oil. This is attributed to the formation of a complex boundary lubrication film mainly composed of the oxides of iron, titanium and lanthanum as well as the formation of an adsorption film of oleic acid on steel sliding surfaces.