针对防护涂层在受动载时的磨损问题,在动能控制模式的冲击试验机上,通过动力学响应考察了Cr.DLC涂层的冲击磨损行为。响应包括冲击力波形和冲击动能的能量耗散,并以其基体304不锈钢作为对比材料。结果表明:材料的动力学响应差异反映了其抗冲击性的优劣。相同试验条件下,Cr-DLC涂层的冲击力峰值和能量吸收率分别低于304不锈钢约42.0%~51.8%和18.6%-20.8%。此外,还发现在冲击动能相同的情况下,调整速度或质量将会对动力学行为产生显著的影响。质量增大,冲击力峰值降低、接触时间延长;而增加速度仅提升冲击力峰值。通过动力学响应可定性的判断材料抗冲击性能,且与实际磨损结果有较好的吻合。Cr-DLC涂层由于其优异的抗冲击磨损性能以及良好化学稳定性,使其磨痕表面仅有少量的磨损剥落,且磨损氧化现象不明显;304不锈钢的冲击损伤形貌为典型的剥层磨损,材料去除和氧化反应首先发生在表面的剥层。
Aiming at wear issue of the protective coatings when subjected to dynamica loading, the impact wear tests were performed with Cr-DLC coating. The employed machine was controlled by kinetic energy, and the substrate 304 stainless steel was selected as comparative material. The dynamic response was investigated for evaluating the wear behavior, including the waveform of impact force and the energy dissipation. The results show that the impact resistance of the tested materilas can be concluded by the difference of their dynamic responses. Under the same testing situation, the peek impact force and energy absorption rates of the coating are 42.0%-51.8% and 18.6%-20.8%, respectively, lower than that of the steel. In addition, the alteration of mass or impact velocity makes much difference to the dynamic behavior under the same kinetic energy. With the increase of mass, the peek impact force is reduced and the contact time becomes longer, while the increase in velocity only affects the peek force. The dynamic response helps to determine the impact resistance of materials qualitatively, which is in good agreement with the wear results. Due to the excellent properties and chemical stability of Cr-DLC coating, only a few spalling occurred and oxidation behavior was limited. The impact morphology of 304 stainless steel is typical delamination wear. The oxidation reaction and material removal occur on surface delamination layer firstly.