The mechanism of stick-slip phenomenon during friction process at low temperature environment

When a material is immersed in a low-temperature medium, e.g., liquid nitrogen, its Young's modulus and surface roughness will change as the temperature of the material decreases as a result of different friction behaviors. In this study, a high-precision friction test device was constructed to perform a detailed comparative study on the friction properties of a pure copper strand immersed in liquid nitrogen, air, and water. The force and displacement resolutions of the experimental system were as high as 0.01mN and 0.03 mu m, respectively. It was found that the stick-slip phenomenon in the liquid nitrogen was significant, while the slope of the stick-slip was larger than those observed in the air and water media. These experimental results were simulated using a spring-slider model that considered the influence of hydrophilicity on surface roughness. The roughness was shown to change the amplitude of the friction curve with time, while the slope of the stick-slip was dominated by the modulus' magnitude variety.