Authors: Hyung Goun Joo; Da Quan Zhang; Li Xin Gao; Tao Liu; Kang Yong Lee
Addresses: Stress Analysis and Failure Design Laboratory, School of Mechanical Engineering, Yonsei University, Seoul 120-749, Korea ' Department of Environmental Engineering, Shanghai University of Electric Power, Shanghai 200090, China ' Department of Environmental Engineering, Shanghai University of Electric Power, Shanghai 200090, China ' Department of Environmental Engineering, Shanghai University of Electric Power, Shanghai 200090, China ' State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Liaoning 116024, China
Abstract: WC-Ni composite coatings were prepared by on the mild steel substrates by high-temperature sinter-brazing. The microstructure of the brazing coatings was characterised by the scanning electron microscopy (SEM). The chemical composition was determined by energy dispersive X-ray (EDX). The corrosion behaviours were investigated by using electrochemical impedance spectroscopy and potentiodynamic polarisation curves in 0.5M HCl solution. It shows that the brazed WC/Ni coatings have good corrosion-resistance property in acidic chloride media. The anodic polarisation process reflects mainly the behaviour of Ni binder. The general corrosion degradation of the brazed WC/Ni coatings presents a preferential dissolution of Ni binder. The insoluble oxidation products deposit on the WC/Ni coatings surface. This leads to a pesuo-passivity property and reduces the dissolution rate of the brazed WC/Ni coatings.
Keywords: sinter brazing; corrosion resistance; cladding coatings; electrochemical polarisation; tungsten carbide; surface science; cermet coatings; nickel; mild steel substrates; microstructure; chemical composition.
International Journal of Surface Science and Engineering, 2014 Vol.8 No.4, pp.380 - 391
Received: 22 Feb 2013
Accepted: 21 Sep 2013
Published online: 23 Nov 2014 *