Optimization of loading factor of Nanocomposite Coatings deposited by Physical Vapor Deposition

Abstract

The Physical Vapor Deposition (PVD) is a technique in which metal or metal alloy vapors are deposited on the surface of the tools in a vacuum chamber. The positioning of the tools i.e. fixture and loading factors (% area of the chamber filled with tools) influence in the flow of the vapors in the chamber. This results in a significant effect on the coating characteristics which affect the film properties. Nano Composite Coatings i.e. AlTiN/Si3N4 (nACo) or AlCrN/Si3N4 (nACRo) deposited by the PVD technique show superior hardness, toughness, heat and oxidation resistance. The adhesion and diffusion of these Nano structured films on substrate depend on proper surface cleaning steps and loading factors. In present work, nACo and nACRo coatings were done by changing the loading factors (50% to 75%) for coating. These coated samples were characterized and the tribological, mechanical and wear properties were studied. It was observed that; fixture, surface cleaning steps of substrate and vacuum surface areas (loading factors) have influenced the adhesion and thickness properties of the coated films. The 75% loading factors greatly enhance the efficiency of tools coated with both nACo and nACRo structured films.