Endurance of TiAlSiN coatings: Effect of Si and bias on wear and adhesion

In this work, the endurance of TiAlSiN nanocomposite thin films subjected to tribological solicitation is studied. These coating were deposited on M2 steel substrate by magnetron sputtering. Dry sliding experiments were conducted at ambient temperature against WC–Co ball. Coefficients of friction, wear rates and endurances were correlated with the composition, microstructure, mechanical properties, residual stress and adhesion of the coatings. The hardness and elastic modulus were found dependent not only on the composition but also on the residual stress induced by the deposition process. Friction coefficient was found to be independent on Si content while the wear rate is strongly reduced for higher Si contents. The formation of a nanocomposite microstructure, the amount of amorphous Si-based phase and both, wear resistance and adhesion are shown as the critical factors to determine the endurance of the coating.

Research highlights
► Tribological properties of nc-TiAlN/a-Si3N4 thin films.
► Deposition parameters influence the Si content and residual stress.
► Increasing Si content enhances mechanical properties and wear resistance.
► Higher Si3N4 amorphous phase increases toughness and adhesion of the coating.
► Si content and deposition parameters are critical factors to control the endurance of the coating.