Influence of Variable-Depth Groove Texture on the Friction and Wear Performance of GCr15-SiC Friction Pairs Under Water Lubrication

Surface texturing is an effective technology for enhancing lubrication and anti-wear properties through hydrodynamic effects and secondary lubrication. In this study, two types of variable-depth groove textures were designed to enhance the lubrication performance of friction pairs. Based on theoretical analysis, the coefficient of friction (COF), wear characteristics, and triboelectric open-circuit voltages produced by different textures were evaluated in a series of experiments. Using a friction testing setup, scanning electron microscopy, energy dispersive spectrometry, an electrometer (Keithley 6514), Raman spectroscopy, surface microtopography, and lubrication mechanisms were revealed. First, two types of variable-depth groove textures were designed based on computational fluid dynamics. Second, SiC samples with these textures were fabricated using laser surface texturing technology, and ball-disk rotary friction experiments were performed. During the friction tests, the shallow inner and deep outer (SDT) groove textures exhibited a lower COF at medium and low speeds under varying loads. Finally, the lubrication mechanism was attributed to the synergistic effect of four factors: the hydrodynamic effect of the lubricant, enhanced ability of debris expulsion, oxide tribofilms at the interface, and polarization electric field generated at the solid-liquid interfaces between the lubricant and friction pair. The results indicate that the minimum COF of the SDT texture can be reduced to 0.025. These insights offer valuable guidance for design methods and new lubrication mechanisms for enhancing the lubrication and anti-wear properties of friction pairs in mechanical systems.