剂量对润滑条件下氮离子注入316L不锈钢摩擦学行为的影响

Effect of Dose on Tribological Performance of N^+-Implanted Stainless Steel under Lubrication Conditions

氮化钢零件在工业上获得了广泛应用,但表面N含量对其在润滑条件下摩擦学行为的影响规律及其机理认识不够清楚.通过改变剂量调控316L不锈钢氮离子注入试样表面N含量,研究了剂量对其在润滑条件下摩擦磨损性能的影响规律及其机理,结果对润滑条件下氮化钢零件应用具有重要意义.研究结果发现:剂量从0增加到2×1017 N+/cm2时,边界润滑条件下注入试样的摩擦系数和磨损率以及对摩球磨损率明显降低,且在二烷基二硫代磷酸锌润滑条件下氮离子注入对摩擦磨损性能的改善更为显著;其作用机理为试样表面较高的N含量使二烷基二硫代磷酸锌在摩擦过程中生成链长更短、硬度更高的玻璃态磷酸盐聚合物.但进一步增大剂量对注入试样的摩擦磨损性能影响不大.

Nitridized steel parts have been widely applied in many fields, but the effect of the surface N content on the tribology of the nitridized parts and its mechanism has not been clearly understood. The surface N content of the N^+-implanted 316 L stainless steel samples was controlled by changing the dose, and the influence of the dose on the tribological performance of the N^+-implanted samples under lubrication conditions and its mechanism were studied. It is found that with the increase of the dose from 0 to 2×1017 N^+/cm^2, the friction coefficients, wear rates of both the implanted samples and their counterpart balls decreased, and the improvement of the tribological performance by N ion implantation under zinc dialkyl dithiophosphates lubrication conditions was more obvious. The mechanism was that a higher N content in the implanted layers promoted the formation of the polyphosphate with a shorter chain length and a higher hardness from zinc dialkyl dithiophosphates. However, the influence of the dose on the tribological performance of the implanted samples became unobvious when the dose was further increased to above 2×1017 N^+/cm^2.