www.globaljournal.asia GJESR RESEARCH PAPER VOL. 3 [ISSUE 4] MAY, 2016
ISSN: - 2349–283X
PULSE FREQUENCY EFFECT ON MICROSTRUCTURE, MORPHOLOGY, MICRO HARDNESS AND WEAR RESISTANCE OF ELECTRODEPOSITED Ni-SiC COMPOSITE COATINGS *1 Piyush
Priyadarshi Dept. of Metallurgical and Material Engineering, IIT Roorkee, Roorkee, India e-mail: piyushch@outlook.com
2Monu
kumar (Asst. Professor) Department of Mechanical Engineering, DR. KNMIET Modinagar, India e-mail: monu33tyagi@gmail.com
Abstract: This paper describes the work on Ni-SiC composite coatings produced by pulse electrodeposition on copper substrate. XRD analysis was done for the coated layer and confirms the presence of SiC in the coating. It has been found that SiC was engulfing in Ni matrix so that microhardness and wear resistance property improved. SEM (scanning electron microscopy) and EDS(energy dispersive spectroscopy) were done to investigate microstructure, morphology and SiC (vol.%) reinforcement in Ni-SiC metal matrix composite(MMCs) coatings. Keywords: Pulse electrodeposition, Ni-SiC, composite coatings, microhardness, wear rate.
1. Introduction Metal matrix composites (MMCs) coatings by electrodeposition technique have been generating significant interest in surface and coatings technology. Electrodeposited nickel is the most widely used coating as it shows good mechanical properties, excellent corrosion resistance, high electrical and thermal conductivity and good magnetic property. Nickel composite coatings are deposited with SiC, Al2O3, ZrO2, TiO2, La2O3, and CeO2 particles [2]. Electrodeposition of Ni-SiC composite in which matrix made by Ni metal and SiC ceramic reinforced in that matrix having very good mechanical properties used in engineering application like automobiles, electronic, textile, ceramic, paper industries, energy sector etc. These composite coatings not only depend on the concentration, size, distribution and nature of the reinforced particles but also on type of solution used and parameters like current density, temperature, pH value, etc [1, 3]. Entrapment of the particulate in composites
depends on suspension and parameters like current density, pH, temperature etc gave appreciable effect on hardness and COF [3]. Pulse current can produce deposits with more uniform particle distribution and better surface morphology compared to direct current because it provides Toff time to cathodic substrate during which particulate SiC got enough time to well reinforced in between the Ni matrix and enhanced the composites property [3, 4]. In pulse current compare to dc having lower porosity and improved corrosion resistance [1, 2]. Microhardness for pulse current plated samples was higher than the direct current plated sample and internal stress was lower for it [2, 4, 6]. Also pulse electrodeposition method plays a crucial role because it is more efficient in fabrication of metals and alloys due to its independently controllable parameters and higher instantaneous current densities compare to other electrodeposition [4]. The properties of metals and alloys can be controlled and improved by modifying their microstructure when using pulse current. It shifted the polarization curve and greatly affected the
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