Viscosity modification of lubricating oil based on high-concentration silica nanoparticle colloidal system |
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Authors: | Xiangyu Liu Nan Xu Weimin Li Ming Zhang Wenjing Lou |
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Institution: | 1. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, People’s Republic of China;2. Qingdao Center of Resource Chemistry &3. New Materials, Qingdao, People’s Republic of China |
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Abstract: | In this study, colloidal systems with SiO2 nanoparticle as viscosity modifier additive were synthesized in the lubricating oil via an in situ Stober sol-gel method. The fluid characters of lubricating oil and viscosity variation were carefully investigated via rheological methods. The results showed that the lubricating oil transformed from Newtonian fluid to non-Newtonian fluid with increasing the concentration of nanoparticles, and smaller particles displayed better thickening effect toward lubricating oil. For the system with highly concentrated nanoparticle (20?wt%), the rheological behavior mainly depends on the size of nano-SiO2. The lubricating oil with smaller nano-SiO2 particles displayed higher structural strength and response rate, resulting in good recoverability after high-speed shear. The viscosity changed with temperature and also displayed a thermo-responsive behavior, which significantly alleviated the effect of shear thinning on the viscosity under high temperature. This study presented a new strategy for effectively tuning the fluid characters and modifying the viscosity of lubricating oils by adding highly concentrated inorganic nanoparticles. |
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Keywords: | Rheological behavior silica nanoparticles suspensions viscosity modification |
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