建立了弹性棘轮模型并用于研究微观形貌参数对摩擦性能的影响,通过研磨和抛光的方法在硅材料表面进行形貌修饰,并采用原子力显微镜和自制微摩擦测试仪分别在纳米和微米尺度下进行摩擦力测量试验.结果表明:硅表面经过形貌修饰后,摩擦力不仅与粗糙峰的斜率有关,而且与接触副的等效曲率半径相关;在纳米尺度下,粗糙峰斜率对摩擦力的影响较大;在微米尺度下,等效曲率半径对摩擦力的影响较大;棘轮模型只适用于斜率影响为主导因素的情况,而弹性棘轮模型由于综合考虑了形貌斜率和等效曲率半径的影响,能够更好地描述不同尺度接触副的摩擦规律.
An elastic ratchet model was developed to study the effect of micro surface topography parameters on friction performance. Micro surface texturing was made on silicon wafer surface by grind and polish processes, and experiments were carried out at nano and micro scale by AFM and a customized micro-tribotester. Results show that the friction force of textured silicon surface is affected not only by asperity slope but also equivalent radius of curvature of contact pairs, and dominated by asperity slope at nano scale, equivalent radius of curvature at micro scale. Ratchet model coincides with experimental results only in slope dominating case, and elastic ratchet model could better depict friction phenomena at different scales for its consideration of slope and equivalent radius of curvature.