In this work, brass (H65) was selected as the friction pair material, and two kinds of surface textures, i.e. square pit textured (SPT) surface and groove textured (GT) surface were fabricated on the surface of flat specimens by laser system. The width of pit edges and grooves was 100 μm, the texture spacing was 300 μm, and the texture depth was 20 μm. A series of current-carrying tribological tests was carried out on the ball-on-flat friction and wear testing machine. The normal load was set as 1 N and the input current was set as 1 A. The tribological properties of the surface texture and smooth surface under current-carrying condition were compared and analyzed. Furthermore, the test process was simulated by thermal-electric-mechanical coupling analysis method, to reveal the effect mechanism of surface texture on the tribological behavior of the electrical contact interface. The friction coefficient of GT surface was low in the initial stage, which gradually increased with the test and reached the same level as that of smooth surface, at about 0.7. While the friction coefficient of SPT surface remained a low value throughout the whole test, which was about 0.4 during the whole test. Similarly, the friction force measured from GT surface was relatively low in the initial stage, which exhibited a sawtooth shape. With the progress of the test, the sawtooth shape feature gradually disappeared, and the anti-friction ability of the GT was gradually alleviated. Therefore, both of the two textured surfaces can reduce the interfacial friction coefficient and friction force to varying degrees, and the ability of SPT surface in reducing friction is the most significant. The vibration analysis results show that the smooth surface generates friction-induced vibration with multi-frequencies during the friction process, which is 100 Hz, 500 Hz and 1 000 Hz. While the vibration signals of the two textured surfaces are very weak, especially for the SPT surface, the vibration intensity is very weak and only one frequency of 100 Hz is detected. In the condition of sliding electrical contact, the increase of friction coefficient will not cause the generation of friction-induced vibration. For the SPT surface and GT surface, the standard deviation of the contact voltage is 0.032 V and 0.05 V, respectively, which is lower than the value calculated from the smooth surface (0.095 V), suggesting that although the surface texture reduces the contact area, the contact voltage can maintain stable as long as there is sufficient conductive contact surface. The wear analysis results show that the smooth surface and GT surface show more serious wear phenomenon. In contrast, the SPT surface wear is slight, and the square pit texture remains intact. The grooves of GT surface are damaged and debris accumulation can be observed, which are the main reasons leading to the gradual loss of anti-friction effect. The finite element analysis results show that the existence of the textured surface can avoid the phenomenon of stress concentration, improve the wear and accordingly reduce the vibration intensity. Although the maximum stress distribution on GT surface also has time-varying characteristics, the stress value on GT surface is larger (90 MPa) and is still distributed on the edge of the groove. Therefore, the anti-friction effect of groove texture is gradually weakened. The simulation analysis of voltage signal and normal displacement signal also provides a reasonable explanation for the tribological behavior of different surfaces. The above research provides a reference for understanding the effect of surface texture on the tribological behavior of electrical contact interface. © 2024 Chongqing Wujiu Periodicals Press. All rights reserved.
