Synergistic lubrication mechanism of friction-induced melting of paraffin on the textured surface

Abstract Under dry friction conditions, friction heat accumulation is a key issue that leads to thermal fatigue, increased wear, and even failure of materials. To address this issue, this study proposes a friction-reducing and lubricating surface based on the synergistic effect of paraffin and surface texture. A ball-on-disk friction tester was utilized to test the textured surface and the composite surface, and the dynamic changes of temperature, friction coefficient and wear amount of the two surfaces were compared during the friction process. Meanwhile, the effect of texture shape on the friction characteristics of the composite surface was explored, and the morphology of the worn surface was observed by scanning electron microscope (SEM). In addition, a numerical model of the composite surfaces was established based on FLUENT software to reveal the influence of texture shape on lubrication performance. The results found that the phase change of paraffin could absorb friction heat and lower the temperature at the friction interface by the degree of 11.2 %. Meantime, the paraffin could provide the lubricating effect, which stabilized friction behavior and reduced friction coefficient and wear mass by the degrees of 69.1-76.8 % and 79.5-86.2 %, respectively. Among five texture shapes, the circle texture coupled with paraffin presented the lowest friction coefficient of 0.054 and mass loss of 1.6 mg. This study provides a solution for the simultaneous improvement of temperature rise, friction and wear for bearings raceway.