【摘要】 运用分子动力学(MD)方法研究了类金刚石(DLC)薄膜的微观磨损行为。首先将晶体碳加热至熔融状态后高速淬火,模拟制备出类金刚石薄膜,然后采用金刚石刀具对薄膜进行表面摩擦,研究了Si原子夹杂含量、压力载荷和摩擦速度对薄膜表面磨损的影响,并分析了微观机理。结果表明,随着Si夹杂含量的增多导致薄膜中sp~2杂化比例升高,薄膜磨损率呈现先下降后上升的趋势,且在夹杂含量为10%左右时达到最小值;刀具压力载荷的增大使磨损率呈线性增加,这与宏观体系的Archard磨损模型一致,载荷的增加能够软化被加工表层从而降低摩擦系数;当刀具摩擦速度变大时,材料的磨损深度减小,导致磨损率降低。更多还原

【Abstract】 Microscopic wear behavior of diamond-like carbon film(DLC) were studied using molecular dynamics(MD) method. Initially, carbon crystals in simulations were heated to molten state and then rapidly quenched to turned to diamond-like carbon films. Subsequently friction processes were conducted by using a diamond tool to investigate the effects of Si impurity content, pressure load and friction velocity on the wear of the film. The micro-mechanism of wear rule was analyzed and compared with previous experiments. The results show that with Si content being increased, sp~2 hybridization fraction in the film also increases, whereas the wear rate firstly decreases and then increases. The minimum wear rate occurs at around the impurity content of 10%. Wear rate increases linearly with the load pressure of the diamond tool, which is in accordance with the macroscopic Archard’s wear model. Besides, the increase of load may soften the film surface and thus decrease the friction coefficient. The increase of friction velocity decreases wear depth and hence leads to the reduction of wear rate.更多还原