Tribology of Cu-Alloyed Carbon-based Coatings in Dry Sliding and Lubricated Steel Contact

摘要

C-based coatings can provide suitable properties for applications where good wear resistance and low friction are required. In this work, DLC coatings alloyed with Cu will be presented as a part of a more extended work on the tribological behaviour in dry and lubricated contacts of C-based coatings with different metal contents (Cu and W) deposited by DC magnetron sputtering. All deposited coatings have compact morphologies with amorphous or nanocrystalline structures. The coatings were tribological tested in dry and lubricated conditions with different oils at different temperatures. In dry sliding the friction coefficient increases as the test temperature increased for non hydrogenated coatings while for hydrogenated ones a decrease of the friction was observed. For H-free coatings in lubricated contact a significant reduction of the friction in relation to dry sliding conditions was observed. The results of the friction are influenced by the type of lubricant, being the lowest values achieved with olive oil. When the coatings were tested with Poly-Alpha-Olefin oil the metal content contributes to a significant reduction of the friction, particularly at the highest tested temperatures. The coating wear rate for dry conditions showed an increasing trend with rising temperature, while in lubricated conditions its values is almost constant and very low.