Improving the properties of mild steel by ternary multilayer composite coating via electrodeposition route

Abstract

A wide range of metal-oxides exhibit fascinating properties and multiple functionalities that could address challenge of physical and mechanical deterioration of materials in service. In this study, Zn-ZrO₂, Zn-SiC and Zn-ZrO₂-SiC composite coating was fabricated from zinc based sulphate electrolyte at constant current density, depth of immersion, distance between anode and cathode with time of deposition. The effect of particle on the physical behaviour of the coating was examined by coating gauge tester for the coating thickness and coating texture. The mechanical properties in term of hardness and wear characteristics were examined using high diamond micro-hardness tester and three body abrasive MTR-300 testers with dry sand rubber wheel apparatus with 5 N and 15 N, respectively. The coating stability in harsh region was examined with isothermal furnace at 200 ^oC for 4 h. The structural behaviour was investigated using scanning electron microscope attached with energy dispersion spectroscopy (SEM/EDS). The result shows that significant improvements in wear and hardness properties are linked to the microstructural modification of the coating as a result of the embedded particulate. The strengthening behaviour was improved with about 98% of coating efficiency. The progression of the coating thickness and texture were in line with other results obtained.

KEY WORDS: Microstructure, Strengthening effect, Mechanical properties, Co-deposition, Zn-ZrO₂-SiC

Bull. Chem. Soc. Ethiop. 2016, 30(3), 449-456.

DOI: http://dx.doi.org/10.4314/bcse.v30i3.13