Electrochemical behavior of single layer CrN, TiN, TiAlN coatings and nanolayered TiAlN/CrN multilayer coatings prepared by reactive direct current magnetron sputtering

William Grips, VK and Barshilia, Harish C and Ezhil Selvi, V and Kalavati, - and Rajam, KS (2006) Electrochemical behavior of single layer CrN, TiN, TiAlN coatings and nanolayered TiAlN/CrN multilayer coatings prepared by reactive direct current magnetron sputtering. Thin Solid Films, 514 (1-2). pp. 204-211.

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Abstract

The corrosion behaviors of single layer TiN, CrN, TiAlN and multilayer TiAlN/CrN coatings, deposited on steel substrate using a multi-target reactive direct current magnetron sputtering process, were studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical13; impedance spectroscopy (EIS). The total thickness of the coatings was about 1.5 x3BC;m. About 0.5 x3BC;m thick chromium interlayer was used for improved adhesion of the coatings. The potentiodynamic polarization measurements showed that for all the coatings the corrosion potential shifted13; to higher values as compared to the uncoated substrate. Similarly, the corrosion current density decreased for coated samples, indicating better corrosion resistance of the coated samples. The multilayer coatings of TiAlN/CrN exhibited superior corrosion behavior as compared to the single layer coatings. The Nyquist and the Bode plots obtained from the EIS measurements were fitted by appropriate equivalent circuits to calculate the13; pore resistance, the charge transfer resistance and the capacitance. These studies revealed that the pore resistance was lowest for TiN coatings, which increased for TiAlN coatings. TiAlN/CrN multilayer coatings exhibited highest pore resistance. No significant change in the capacitive13; behavior of the coatings was observed, suggesting minimal morphological changes as a result of immersion in the electrolyte. This could be attributed to shorter immersion durations. These studies were confirmed by examining the corroded samples under scanning electron microscope.13; Preliminary experiments conducted with additional interlayer of electroless nickel (5.0 x3BC;m thick) have shown significant improvement in the corrosion resistance of the coatings.13; xA9; 2006 Elsevier B.V. All rights reserved.

Item Type:	Article
Additional Information:	Copyright for this article belongs to Elsevier Science Ltd.
Uncontrolled Keywords:	TiN;CrN;TiAlN;TiAlN/CrN multilayers;Sputtering;Electrochemical behavior
Subjects:	CHEMISTRY AND MATERIALS > Composite Materials
Depositing User:	M/S ICAST NAL
Date Deposited:	29 Jan 2007
Last Modified:	13 Aug 2015 09:41
URI:	http://nal-ir.nal.res.in/id/eprint/3989

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