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Journal of Nanomaterials
Volume 2011, Article ID 137498, 6 pages
http://dx.doi.org/10.1155/2011/137498
Research Article

Microstructure and Corrosion Behavior of Ni-Alloy/CrN Nanolayered Coatings

1Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan
2Department of Materials Science and Engineering, Ming Chi University of Technology, Taipei 24301, Taiwan

Received 23 April 2010; Accepted 19 August 2010

Academic Editor: Bo Zou

Copyright © 2011 Hao-Hsiang Huang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Ni-alloy/CrN nanolayered coatings, Ni-Al/CrN and Ni-P/CrN, were deposited on (100) silicon wafer and AISI 420 stainless steel substrates by dual-gun sputtering technique. The influences of the layer microstructure on corrosion behavior of the nanolayered thin films were investigated. The bilayer thickness was controlled approximately 10 nm with a total coating thickness of 1 μm. The single-layer Ni-alloy and CrN coatings deposited at 350C were also evaluated for comparison. Through phase identification, phases of Ni-P and Ni-Al compounds were observed in the single Ni-alloy layers. On the other hand, the nanolayered Ni-P/CrN and Ni-Al/CrN coatings showed an amorphous/nanocrystalline microstructure. The precipitation of Ni-Al and Ni-P intermetallic compounds was suppressed by the nanolayered configuration of Ni-alloy/CrN coatings. Through Tafel analysis, the Ecorr and Icorr values ranged from –0.64 to –0.33 V and 1.42×105 to 1.14×106 A/cm2, respectively, were deduced for various coating assemblies. The corrosion mechanisms and related behaviors of the coatings were compared. The coatings with a nanolayered Ni-alloy/CrN configuration exhibited a superior corrosion resistance to single-layer alloy or nitride coatings.