Diamond-like coating for piston ring surfaces, piston ring and processes for preparing the same

摘要

The present invention relates to a diamond-like coating for piston ring surfaces, comprising, an underlayer, a gradient layer and an AM layer, wherein the AM layer is a diamond-like coating doped with doping elements. The doping elements are one or a combination of at least two selected from the group consisting of Cr, Si and Ti, and the content thereof shows a cyclical change in a form of a sine wave fluctuation along with the thickness change of the AM layer. As compared with the conventional single-layer structure or gradient layer structure, the AM layer of such diamond-like coating has a multi-cycle transition structure since the content of the doping elements in the AM layer of such diamond-like coating shows a cyclical change in a sine wave fluctuation form. On the basis of having high wear-resistant and low friction coefficient, it is beneficial to decrease the internal stress of the coating, increase the tenacity of the coating, ensure the increase of the thickness of diamond-like coating, and improve the durability of piston ring of diamond-like coating at the same time.