Effect of metal vapor vacuum arc-implanted Cr on the electrochemical behavior of CrN-coated steels
- PDF / 1,656,462 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 2 Downloads / 191 Views
Shih-Chun Chung Materials Research Laboratories, ITRI, Hsinchu, Taiwan 300, Republic of China
Sheng Han National Taichung Institute of Technology, Taichung, Taiwan 404, Republic of China
Jyh-Wei Hsu, Xing Jian Guo, and Han C. Shiha) Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China (Received 2 December 2003; accepted 13 May 2004)
Using cathodic arc plasma to deposit CrN on the steel has been explored and extensively studied to improve the wear and corrosion resistance of the steel structures. Metal vapor vacuum arc (MEVVA) source implantation is a novel and profitable surface-modification process coupled with the cathodic arc plasma. The effect of the MEVVA-implanted chromium on the corrosion behavior in form of Cr/steel, CrN/steel, and CrN/Cr/steel was evaluated in an aerated 0.1N HCl solution. The composition and structure of the MEVVA-implanted chromium and the cathodic arc plasma deposited CrN on steel were both examined by x-ray diffraction and transmission electron microscopy. The polarization resistance (Rp) of all samples was measured and compared with the results obtained from electrochemical impedance spectroscopy simulated by the equivalent circuit, to interpret the effect of MEVVA-implanted chromium on the corrosion mechanism of the CrN/Cr/steel. The corrosion products associated with the microstructures were analyzed by electron probe x-ray microanalyzer. The results indicated that the corrosion resistance of the CrN-coated steel was significantly enhanced by the MEVVA-implanted chromium in the CrN/Cr/steel assembly. I. INTRODUCTION
Transition metal-nitride coatings have been explored and extensively applied to the improvement of the wear and corrosion resistance of the tool components. Chromium-nitride coated steels produced by cathodic arc plasma deposition (CAPD) have advantages: low internal stress, good adhesion, and good chemical inertness.1 However, defects in the coating (inclusions, cracks, and pinholes) may be formed during the deposition process, and thus limit the use of these methods as an effective protective coating. The major corrosion problem of the coated steel is that these defects may create direct paths between the exposed substrate and the corrosive environment. An application of an intermediate layer between the substrate and the coating is thus to limit the effect of the defects on the corrosion resistance of the substrate.2–4 The intermediate layer can be prepared by a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2004.0309 2448
http://journals.cambridge.org
J. Mater. Res., Vol. 19, No. 8, Aug 2004 Downloaded: 16 Mar 2015
several techniques, such as Cr electroplating.5 Ni/P electroless plating3,4 and PVD-Ti or PVD-Cr methods.6,7 Ion implantation has been used to improve surface properties, such as wear, fretting, corrosion, and oxidation resistance. The final surface microstructures of the ion-implanted steels are from stable to metastable or to amorphous s
Data Loading...
