Tribological characterization of diamond-like carbon films on nonledeburitic high-speed steels

Hydrogenated diamond-like carbon (DLC) films were deposited on as-tempered nonledeburitic high-speed steel (NHSS) substrates (0–5–1–3Ti–2Nb grade) by capacitively coupled RF glow discharge in a methane atmosphere. The substrates were cleaned with an argon flux before coating deposition. Coatings of 1-μm thickness, good smoothness and adhesion were successfully produced. Microscale abrasive wear tests and field emission scanning electron microscopy were employed to evaluate wear resistance and morphology of the DLC films, substrate–film boundaries and worn components. The wear coefficient of the steel substrates was less than that of M2 tool steel, whereas that for the DLC layer corresponded to the value previously reported for titanium aluminium nitride. Certain decohesion micromechanisms in the NHSS samples after microscale abrasion testing were similar to these found in fractured specimens. Structural influences on the results are discussed.