Thick yet tough TiN coatings deposited by filter cathode vacuum arc technology

Abstract

There are some high requirements for mechanical property to protective coatings of turbojet engine compressor blades as the appearance of extreme service conditions. The hard coating with high toughness, good adhesion, good wear resistance and excellent load carrying capacity is a potential coating for extreme service conditions in the future. Thick yet tough TiN hard coatings were successfully deposited on 304L stainless steel substrates by magnetic filtered cathodic vacuum arc technology. The morphology, structure and properties of the coatings were studied by SEM and XRD, etc.The results show that the continuous growth of TiN coatings attributed to periodic high energy ion bombardment which can suppress the large grain size and reduce the internal stress. The thickness of TiN coating can reach to 50 μm and the deposition rate was close to 0.2 μm/min. At the same time, the stable non stoichiometric TiN_0.9 can be formed by controlling the constant N₂ flow rate, which can improve the toughness of TiN coatings. All TiN ciatings belong to superhard coating and the max value of hardness and modulus of elasticity were 38.24 GPa and 386.53 GPa respectively. TiN coatings have good adhesion and excellent toughness.The highest <i> <inline-formula><tex-math id="Z-20200510122827-1">\begin{document}$ H/E^{*} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20200036_Z-20200510122827-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20200036_Z-20200510122827-1.png"/></alternatives></inline-formula></i> and <inline-formula><tex-math id="Z-20200510122827-2">\begin{document}$ H^3/E^{*2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20200036_Z-20200510122827-2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20200036_Z-20200510122827-2.png"/></alternatives></inline-formula>rate of TiN coating can reach to 0.0989 and 0.3742. Thick yet tough TiN hard coatings have excellent wear resistance with the lowest friction coefficient of 0.26.