Novel high wear resistant diamond-like carbon coatings deposited by magnetron sputtering of carbon targets

Abstract

A series of new diamond-like carbon (DLC) coatings has been produced by magnetron sputtering using in-house equipment. The new hydrogen-free pure carbon coatings were deposited by sputtering carbon targets in a pure argon atmosphere. With a metallic interlayer, they have shown improved tribological properties when compared with conventional hydrogenated DLC in pin-on-disc and reciprocating wear tests. The films have also shown the ability to perform in oil, water and dry environments, and to protect the counterpart. The method of ball cratering on wear tracks provided taper sections to allow the analysis of coating wear, interface condition and failure mechanisms. Wear rates as low as 3 × 10−17 m3/N m are shown for 100 N, 10000 cycle reciprocating wear tests in air and in water. Scratch tests have been used to assess coating adhesion with critical loads as high as 70 N. Results from nano-indentation, Raman spectroscopy, electron energy loss spectroscopy and X-ray diffraction are also reported.