L.F. Bonetti

Tribological and mechanical properties of DLC film obtained on metal surface by an enhanced and low-cost pulsed-DC discharge

A new, low-cost, enhanced pulsed-DC PACVD deposition system was designed and tested to evaluate its capacity to produce quality DLC films. The main focus of the study was to attain DLC films with low friction coefficients, low total stress, a high degree of hardness, and very good adherence to the substrates on depositions covering a large area at a high growth rate. A summary of degree of hardness, resulting friction coefficients, deposition rates, total stress, adherence, and structural properties as functions of the pulsed-DC voltage and pulse characteristics are presented in this paper.

Adherent diamond-like carbon coatings on metals via PECVD and IBAD

Adherent and low-stress a-C:H films were deposited on Ti6Al4V and stainless steel substrates using PECVD and IBAD techniques. An amorphous silicon interlayer was applied to improve the adhesion of the a-C:H films on the metal substrates. The XPS technique was employed to analyze the chemical bondings within the interfaces. The elemental composition and atomic density of the films were determined by ion beam analysis. The film microstructure was studied by means of Raman scattering spectroscopy. The mechanical properties were determined by means of stress and hardness measurements. The adherence was evaluated by means of scratch tests. The tests showed that the composition, the microstructure, and the mechanical properties of the films depend on the intensity of the ion bombardment and on the ion current.