Pulse Electrocodeposited Ni–WC Composite Coating

Abstract

In the present work, tungsten carbide (WC) particulate of average size 10 mm were electrocodeposited in the nickel metal matrix, to form metal matrix composite (MMC) coating over the EN8 steel substrate. The electrodeposition of Ni-WC particulate composite coating was carried out using the Watt's bath under the influence of varying current density and duty cycle. It was found that current density of 0.02 A/ cm 2 was sufficient to start the codeposition kinetics. But, good quality of electrodeposition was obtained at a current density of 0.04 A/cm 2 . The WC particulate entrapment and distribution of WC particles in Ni matrix according the variation in experimental parameters has been reported. The dense and compact microstructure was obtained at a current density of 0.04 A/cm 2 and duty cycle of 30%. Microhardness and corrosion resistance properties of composite coating were also evaluated and reported. INTRODUCTIONSurface modification, with the formation=deposition of overlaying layer of metal matrix composite (MMC), provides enhanced mechanical, tribological, and corrosion resistance properties. During the last few decades, researchers have attempted to improve those properties through electrocodeposition of hard particles such as Al 2 O 3 [1-4], TiO 2 [5, 6], SiC [7-9], ZrO 2 [10, 11], WS 2 [12], and Si 3 N 4 [13,14] in different metal matrixes (Ni, Cr, Co, etc.). Nickel is a most suitable metal, among all metal matrixes due to its good chemical compatibility with the other metal and alloys [18]. Moreover, it imparts very good corrosion resistance property to the coated surface. Tungsten carbide is a hard ceramic having high thermal stability and good dispersion properties which lead to high wear and thermal resistance properties of the coating. Deposition of electrically nonconductive tungsten carbide particles alone is very difficult, as it produces obstruction to obtain dense interface of metal-carbide during the electrodeposition process, but it can be easily codeposited with a transition group of elements. Although there are a number of surface coating techniques available, but the electrodeposition process has drawn significant attention because it is a nonthermal process, technologically feasible, easily controllable, economically superior technique to produce a MMC. It is based on the uniform entrapment of second-phase hard particles within the metal matrix.Although many research papers have been reported in the area of WC composite coating through direct current

The effect of current density on microstructural homogeneity, hardness, fracture toughness and electrochemical behavior of electrodeposited Cu-0.5Co/WC nano-composite coating

“…The in uence of current density on the tungsten carbide particles distribution, some mechanical properties, and corrosion behavior of coating was analyzed. The present Cu-Co/WC nano-composite coatings showed a signi cant improvement in hardness, fracture toughness, and corrosion resistance as compared to the previous composite coatings [2][3][4]. These improvements mainly depended on the nature and content of the tungsten carbide co-deposited particles, as well as on their distribution in the metallic matrix.…”

“…Electrochemical deposition has a widespread use in nanotechnology since it can be used to ll three-dimensional features at room temperature with good control of thickness and morphology [1]. During the last few decades, researchers have attempted to improve the properties through electrocodeposition of hard particles such as WC, Al 2 O 3 , SiC, and Si 3 N 4 [2][3][4][5] in various metal matrix materials such as Ni and Cu [2,3]. The copper electroplates are widely used in engineering applications due to their high electrical and thermal conductivity, proper ductility, and required corrosion resistance.…”

Selection of Wear Resistive Nano coating in En8 Steel

“…The advantage of this method is uniform distribution of nano particles, reduction of waste materials [25], and high hardness heat resistance due to nano particles [26]. Few nano composite materials like Al2O3, TiO2, SiC [27][28][29][30][31][32][33][34][35] Ni-WC [36] etc., are coated using this method. Pulse current deposition method is a type of electro deposition method through which tribological properties are enhanced [37].…”

“…Few nano particles like Al2O3, TiO2, SiC, ZrO2, WS2, Si3N4 improve tribological properties through electro deposition method [39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Nickel nano composite coating was reported as suitable material due to good corrosion resistance [36]. Tungsten carbide high thermal and wears resistance and also good dispersion properties.…”

“…Tungsten carbide high thermal and wears resistance and also good dispersion properties. I-WC coating on EN8 material through pulsed current electro deposition process shows better tribological properties [36]. Ni-P-Al2O3 nanocomposite coating showed higher hardness and wear resistance compared with plane Ni-P, this coating technique was developed by electroless technique [11].…”