WC–Ni composite coatings were prepared on the mild steel substrates by high temperature sinter brazing. Potentiodynamic polarisation was performed on the coated sample immersed in 3%NaCl solution. Two limited current plateaus appear in the anodic polarisation curve. The first limited current plateau is attributed to the formation of Ni and Cr oxide, while the second corresponding to W oxide. The surface morphology observation and composition analysis after anodic polarisation were investigated by the scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) spectroscopy. The elemental concentrations in the immersion solution were studied with inductively coupled plasma (ICP) spectroscopy. It shows that the selective dissolution of Ni base binder alloy as well as the electrochemical dissolution of WC exists during the anodic polarisation process.
ZhaoWMWangYHanTWuKY and XueJ: ‘Electrochemical evaluation of corrosion resistance of NiCrBSi coatings deposited by HVOF’Surf. Coat. Technol.2004183118–125.
2.
BuangAPLiuRWuXJ and YaoMX: ‘A study on abrasive resistance of Ni-based coatings with a WC hard phase’J. Coat. Technol. Res.20085513–534.
3.
SerresNHlawkaFCostilSLangladeC and MachiF: ‘Microstructures and mechanical properties of metallic NiCrBSi and composite NiCrBSi-WC layers manufactured via hybrid plasma/laser process’Appl. Surf. Sci.2011257, 5132-5137.
4.
BaoJNewkirkJW and BaoS: ‘Wear-resistant WC composite hard coatings by brazing’J. Mater. Eng. Perform.200413385–388.
5.
LuSP and KwonOY: ‘Microstructure and bonding strength of WC reinforced Ni-base alloy brazed composite coating’Surf. Coat. Technol.200215340–48.
6.
StackMMMathewMT and HodgeC: ‘Micro-abrasion–corrosion interactions of Ni–Cr/WC based coatings: approaches to construction of tribo-corrosion maps for the abrasion–corrosion synergism’Electrochim. Acta201156, 8249-8259.
7.
SouzaVAD and NevilleA: ‘Mechanisms and kinetics of WC-Co-Cr high velocity oxy-fuel thermal spray coating degradation incorrosive environments’J. Therm. Spray. Technol.200615106–117.
8.
LekatouAZoisD and GrimanelisD: ‘Corrosion properties of HVOF cermet coatings with bond coats in an aqueous chloride environment’Thin Solid Films200851, 5700-5705.
9.
de BozziniBGaudenziGPFanigliuloA and MeleC: ‘Anodic behaviour of WC-Co type hardmetal’Mater. Corros.200354295–303.
10.
ChoJEHwangSY and KimKY: ‘Corrosion behavior of thermal sprayed WC cermet coatings having various metallic binders in strong acidic environment’Surf. Coat. Technol.2006200, 2653-2662.
11.
SutthiruangwongS and MoriG: ‘Corrosion properties of Co-based cemented carbides in acidic solutions’Int. J. Refract. Met. Hard. Mater.200321135–145.
12.
SouzaVAD and NevilleA: ‘Mechanisms and kinetics of WC-Co-Cr high velocity oxy-fuel thermal spray coating degradation incorrosive environments’Mater. Sci. Eng. A2003A352202–211.
13.
ZhangDQLiuTJooHGGaoLX and LeeKY: ‘Microstructure and corrosion resistance of the brazed WC composite coatings in aerated acidic chloride media’Int. J. Refract. Met. Hard. Mater.201235246–520.
14.
LuSPKwonOY and GuoY: ‘Wear behavior of brazed WC/NiCrBSi (Co) composite coatings ’Wear2003254421–428.
15.
LiQLeiTC and ChenWZ: ‘Microstructural characterization of WCp reinforced Ni–Cr–B–Si–C composite coatings’Surf. Coat. Technol.1999114285–291.
16.
FernandesCMSenosAMRVieiraMT and AntunesJM: ‘Mechanical characterization of composites prepared from WCpowders coated with Ni rich binders’Int. J. Refract. Met. Hard. Mater.200826491–498.
17.
StackMMMathewMT and HodgeC: ‘Micro-abrasion–corrosion interactions of Ni-Cr/WC based coatings: approaches to construction of tribo-corrosion maps for the abrasion–corrosion synergism’Electrochim. Acta201156, 8249-8259.
18.
SunDWhartonJAWoodRJKMaL and RainforthWM: ‘Microabrasion-corrosion of cast CoCrMo alloy in simulated body fluids’Tribol. Int.20094299–110.
19.
M, Pourbaix: ‘Atlas of electrochemical equilibria in aqueous solutions’28–29; 1974Houston, TXNACE.
20.
LekatouAZoisDKarantzalisAE and GrimaneliD: ‘Electrochemical behaviour of cermet coatings with a bond coat on Al7075: pseudopassivity, localized corrosion and galvanic effect considerations in asaline environment’Corros. Sci.201052, 2616-2635.
21.
HumanAM and ExnerHE: ‘The relationship between electrochemical behaviour and in-service corrosion of WC based cemented carbides’Int. J. Refract. Met. Hard. Mater.19971565–71.
22.
TomlinsonWJ and LinzellCR: ‘Anodic polarization and corrosion of cemented carbides with cobalt and nickel binders’J. Mater. Sci.198823914–918.
23.
SutthiruangwongSMoriG and KöstersR: ‘Passivity and pseudopassivity of cemented carbides’Int. J. Refract. Met. Hard. Mater.200523129–136.
24.
ZhengLNevilleAGledhillA and JohnstonD: ‘An experimental study of the corrosion behavior of nickel tungsten carbide in some water-glycol hydraulic fluids for subsea applications’J. Mater. Eng. Perform.20101090–98.
25.
KarinMA and LennartB: ‘Oxidation and dissolution of tungsten carbide powder in water’Int. J. Refract. Met. Hard. Mater.200018121–129.
