The synergistic mechanism of transition layer and transfer layer on dry sliding wear of multi-layered diamond-like carbon (DLC) coating at wide temperature

The wear resistance of 17-4PH stainless steel was improved at wide temperature (25-200 degrees C) by depositing multi-layered Cr/CrC/DLC coating. The results showed that the lubricating effect of the transfer layer led to a reduction of the friction coefficient to 0.03. DLC coating had a protective effect on the 17-4PH substrate, and the surface of the coating was basically not worn at 25-100 degrees C. This study focused on the wear mechanism and frictional chemical reaction mechanism of multi-layered coatings at wide temperatures. With the increase of temperature, the wear mechanism of DLC coating changed from abrasive wear to adhesive wear, and finally delamination. The complex tribochemical reaction in the wear process led to the dynamic change of its graphitization transformation, which affected the formation of the transition layer and the change in surface mechanical properties of the coating. This was mainly because the transition layer Cr/CrC and Si3N4 played a role in inhibiting the graphitization transformation of DLC layer during the wear process, thus affecting the friction properties of DLC.