Author : Jayabala D 1
Date of Publication :1st December 2017
Abstract: In Electroless nickel phosphorus coatings, the corrosion and wear resistance is determined by the percentage weight of phosphorus in the coating. In order to improve the sustainability of Nickel- Phosphorus coating on a substrate subjected to wear and corrosion during use, by using varying temperature and pH levels, bilayer and duplex coating are coated on the sample and a comparative study was conducted along with the conventional mono-layer coating and the results were analyzed. Bilayer and duplex coatings constituted of two layers of 10 micrometers, each was prepared according to three distinct configurations (medium Phosphorous, High Phosphorous, and a Duplex layer). The hardness characteristics of duplex coatings are influenced by the hardness of Ni3P phase in the coatings which are found to be more stable and is obtained by heat treatment after the coating process is completed. The duplex coated sample is heat-treated to check whether there is any change in the corrosion properties while increasing the surface hardness. The wear test was conducted on a pin on disc apparatus, corrosion testing method used was salt spray corrosion testing, surface hardness / micro hardness was calculated using a micro Vicker’s hardness tester.
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