Research On The Friction And Wear Properties Of Single Crystal Silicon Under The Condition Of Dry Sliding

With the rapid development of science and technology, the traditional lubricating mode is harder to satisfy actual conditions, some researchers focus on the study of dry-friction under the development trend of micromachine and high-speeding in moving parts. Single-crystal silicon is the basis materials of MEMS, so the friction and wear performance of silicon under the dry-friction condition will directly affect the physical and mechanical properties of MEMS. Surface texturing and working conditions are important factors influencing the performances of friction. Take these two factors into consideration, the friction and wear performance, the characteristics of wear morphology and the wear mechanism about silicon are investigated.Rubbing pairs of Si3N4/Si, GCr15/Si and Agate/Si are selected. Friction and wear properties of Single-crystal silicon are tested with the help of UMT-2friction and wear tester. The influences of loads, velocities and friction pair material are discussed. The surface morphology and the wear loss of samples is measured by the MicroXAM-3D and computer-metalloscope. The results show that the friction coefficient decreases with the increase of loads or speeds, at the same time, the wear loss increases with the increase of loads or speeds. Rubbing pairs of GCr15/Si has the maximum friction coefficient in this three kinds of friction pair. The study of effect of groove surface shows that the groove on the surface of silicon can either increase the friction coefficient, or anti-friction. The spacing has greater influence than the angle on the friction properties of silicon.The wear performance of silicon scratch under low loads conditions are tested on the nano-scratch tester. The result shows that the depth increases linearly with rising load until load reaches80mN, and then the depth increases rapidly with rising load.Mathematical methods were used to analyze the relationship between surface topographical parameters and tribological properties. The contour fitting, roughness and height distribution about the worn surface were discussed. With the increase of loads or speeds, roughness and R-squared increase.With the instrument of electron microscopy (SEM) and spectrometer(EDS), microscopic analysis and component analysis on the worn surface of silicon were carried on. Results show that the increase of speed can make worn surface becomes smooth, which related to the oxidation and the protection of oxide film. It has similar surface morphology when load changes. Rising load makes working condition worse. Three kinds of friction pair material have three distinct worn surface morphologies, as the component and hardness of different materials has influence on the wear mechanism.