| HAN Lu-juan,GUO Feng.Influence of Oily Additives on Lubrication under Limited Lubricant Supply[J],49(11):204-211 |
| Influence of Oily Additives on Lubrication under Limited Lubricant Supply |
| Received:February 18, 2020 Revised:October 22, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.11.023 |
| KeyWord:oily additives limited lubricant supply hydrodynamic lubrication ultra-violet irradiation film thickness conformal contact |
| Author | Institution |
| HAN Lu-juan |
Qingdao University of Technology, Qingdao , China |
| GUO Feng |
Qingdao University of Technology, Qingdao , China |
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| Abstract: |
| The work aims to study the effect of oily additives on the lubrication films in a slider-on-disc conformal contact under conditions of limited lubricant supply. The conformal contact lubrication film measuring system was used to measure the base oil PAG and the same base oil with oily additives with stearic acid (0.1%) and octadecylamine (0.1%), to generate the variation curve of lubrication film thickness with speed and characterize the adsorption of oily additives on disc surface. Under the conditions of ordinary disc and UV-irradiated disc, the film thickness of PAG with stearic acid was always lower than that of pure PAG. Under the UV-irradiated disc, stearic acid significantly reduced the film thickness. Under the ordinary disc at the lowest speed and the highest speed, the film thickness of PAG with stearic acid reduced by 0.25 μm and 0.64 μm, with drop rate of 44.2% and 22.1%. However, under the UV-irradiated disc, the film thickness decreased by 0.38 μm and 0.91 μm, with drop rate of 61.5% and 41.7%. Moreover, on the UV-irradiated disc, the PAG with stearic acid appeared in the form of droplet due to dewetting from the stearic acid adsorption on the lubrication track and consequently the film thickness decreased. While the PAG with octadecylamine presented less dewetting on the lubrication track and stayed in the form of discontinuous narrow strips. The generated lubrication oil film thickness was almost equal to that from PAG base oil, the decrease of film thickness at the lowest and highest speed was only 0.11 μm and 0.17 μm, and the drop rate of film thickness was 18.2% and 8.1%. When an ordinary disc is used, the weak affinity between the oil film and the adsorption layer of stearic acid on the slider surface is the main cause for the corresponding lubrication oil film thickness being lower than that of pure PAG base oil. Moreover, the UV irradiation promotes the adsorption of oily additives on the lubrication track, and distinctive tension gradient is formed at the lubrication track boundary, which leads to lubricant escape, thus reducing the film thickness. The film thickness produced by octadecylamine is much higher than that of stearic acid due to the difference in polarity of the polar groups, which affects the distribution of lubricant, and the lubricant supply. |
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