Analysis of hardness of nanocrystalline coatings of aluminum-rich Ti1 − x Al x N

Abstract

Titanium aluminum nitride coatings were fabricated by a d.c. magnetron sputtering system from a Ti-Al (60/40wt%) target. Coatings were deposited on steel substrates, at a substrate temperature of 250 • C and a bias voltage of-80 V. The nitrogen flow was varied from 1•5-6 sccm and the Ar flow was kept constant at 20 sccm. The morphology and microstructure of the coatings were analysed by X-ray diffraction and scanning electron microscopy. The results of X-ray diffraction showed the presence of two cubic crystalline phases, TiN and AlN, which were confirmed by X-ray photoelectron spectroscopy. The Vicker hardness was obtained by the effective model of indentation. It was observed that the hardness of the coatings decreases from 22•8-9•5 GPa with an increased nitrogen content from 1•5-4•5 sccm. Subsequently, the hardness increased to 22•1 GPa by increasing nitrogen to 6 sccm. The behavior of hardness with grain size variation is consistent with the Hall-Peth relationship. The high value in the hardness of the coatings is mainly attributed to small grain sizes and the compressive stress present.

Effects of deposition parameters on the structure and properties of ZrN, WN and ZrWN films

“…Solid ceramic thin films that are made of transition metal nitrides, such as ZrWN, CrWN, TiAlN and TiN, are used on cutting and forming tools for various industrial applications where the environment causes abrasive wear and as a diffusion barrier and protective layer [1]. The transition metal nitrides have a low coefficient of friction, a low wear rate, high mechanical hardness, high thermal and chemical stability and their use allows a longer operational life for a cutting tool [2]. Of these transition metal nitride films, ZrWN possesses the best properties as a protective coating for many applications [3].…”

Ultra-High and Near-Zero Refractive Indices of Magnetron Sputtered Thin-Film Metamaterials Based on TixOy

“…A metal target can be used and a high deposition rate is achievable as well. This technique is widely applied to deposit hard, wearresistant, low friction, corrosion resistant, and decorative coatings, as well as coatings with specific optical or electrical properties [4][5][6]. It is especially useful for deposition of high-quality titanium dioxide (TiO 2 ) films at relatively low temperature [7,8].…”