| WANG Pengyang,LONG Wei,ZHAO Zhangxing,MAO Wenyuan,QIAO Yan.Water Lubrication Characteristics of Droplet Texture on SiC Surface[J],53(1):96-104 |
| Water Lubrication Characteristics of Droplet Texture on SiC Surface |
| Received:November 02, 2022 Revised:May 12, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.01.009 |
| KeyWord:silicon carbide droplet texture friction coefficient frictional chemical reaction elastohydrodynamic lubrication |
| Author | Institution |
| WANG Pengyang |
School of Mechatronics Engineering,Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming , China |
| LONG Wei |
School of Mechatronics Engineering,Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming , China |
| ZHAO Zhangxing |
School of Mechatronics Engineering,Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming , China |
| MAO Wenyuan |
School of Mechatronics Engineering,Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming , China |
| QIAO Yan |
School of Mechatronics Engineering,Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming , China |
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| Abstract: |
| Surface micro-texture technology is a new type of lubrication and friction reduction, which is widely used in cutting tools, cylinder liner-piston rings, mechanical seals and other mechanical parts. In recent years, surface micro-texture has been proved to have excellent properties of reducing friction, reducing wear and improving lubrication properties between friction pairs. In this work, the friction-reducing effect of variable-depth micro-texture with droplet shape on silicon carbide material under water lubrication condition was studied and its mechanism was revealed. SiC with a diameter of 50 mm, a thickness of 20 mm, and a surface roughness of 0.02 μm was used as specimen. The LM-20 laser marking machine was used for fabricating the droplet texture and chute texture on the surface of SiC specimen. Furthermore, SEF-680 surface roughness profile shape measuring instrument was used to measure the roughness of the textured surface after processing to ensure that the processed micro-texture was consistent with the designed texture shape and size. In order to match with the SiC specimen, a friction and wear testing machine was independently built. The processed lower specimen was fixed in the oil pool by means of pin connection, and the upper specimen was fixed on the rotating shaft by means of screw thread connection. The shear torque of the friction pair under different load, speed and distribution modes was tested on a self-designed friction testing machine, and the friction coefficient was calculated to evaluate the effect of the droplet texture on the lubrication and friction reduction of the specimen. Furthermore, Scanning Electron Microscope (SEM) and Energy Disperse Spectroscopy (EDS) were used for detecting the surface wear of different specimens and the element distribution on the surface of specimens before and after the test. Finally, the lubrication mechanism of micro-texture in the depth of droplet deformation was proved. Under the synergistic effect of variable-depth elastohydrodynamic lubrication and friction-chemical reaction, the specimen with unilateral droplet texture could achieve better lubrication performance when the lubricative medium flew from small end to large end while the speed increased from 200 r/min to 900 r/min and the stable friction coefficient increased from 0.004 to 0.068. It was much lower than that of the specimens with chute texture and smooth surface under the same working conditions. When the fluid flew from the large end to the small end, the friction coefficient of the specimen with droplet texture was similar to that of the specimen with smooth surface, which was maintained at 0.014-0.114. The bilateral droplet texture had more excellent lubrication and friction reduction effect under heavy load, and could provide stable and relatively small friction coefficient in the speed range of 200-900 r/min. The design of the droplet texture with variable depth on the surface of SiC material can effectively improve the lubrication and friction reduction effect of the system, especially when the lubrication medium flows from the shallow part of the texture to the deep part. It can promote the tribological chemical reaction on the surface of SiC specimen, and the generated oxide film will cover the surface of the specimen to form a protective layer, so that the tribological behavior of SiC ceramics can be improved. |
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