Diamond-like carbon, Si-based interlayer, Deposition temperature, Coating adhesion PACVD

What is it about?

Diamond-like carbon (DLC) films were deposited on AISI 316L stainless steel by using a unipolar pulsed-DC plasma assisted chemical vapor deposition (PACVD) system. In order to improve the adhesion of the DLC films to the substrate, three different silicon-containing interlayers (a-Si:H, a-SiCx:H, and a-SiNx:H) were deposited at two temperatures of 150 and 350 °C using silicon tetrachloride, methane, nitrogen, and hydrogen precursors. The DLC films with silicon-containing interlayers, deposited at 150 °C, did not show appropriate adhesion to the substrate due to the presence of a high amount of chlorine and hydrogen in the structure of the interlayers. By increasing the temperature of the interlayer deposition, the adhesion of DLC films improved significantly. The results of Raman spectroscopy, Nano indentation and adhesion tests showed that the DLC film with a-SiNx:H interlayer exhibited the lowest ID/IG ratio, highest hardness, and highest adhesion to the substrate.

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Why is it important?

• DLC films were deposited on 316L steel by pulsed-DC PACVD at 150 and 350 °C. • a-Si:H, a-SiCx:H and a-SiNx:H interlayers were used to improve the film's adhesion. • The films deposited at 150 °C did not show a suitable adhesion to the substrate. • High amounts of Cl and H in the interlayers decreased film's adhesion. • DLC film with a-SiNx:H interlayer exhibited the highest adhesion to the substrate.