Microstructural evolution and characterization of super-induced MgO composite on zinc-rich coatings

The effect of Zn-MgO deposition prepared through direct electrolytic co-deposition on mild steel was studied.The experiment was conducted at current density between 0.5 and 1 A/cm−2. The morphologies of the coated surfaces were characterized using Atomic Force Microscope (AFM), high resolution Nikon Optical Microscope (OPM) and Scanning Electron Microscopy attached with Energy Dispersive Spectrometer (SEM/EDX). The corrosion behavior was studied using linear potentiodynamic polarization method in 3.5% simulated environment. The phase change was evaluated using X-ray Diffractogram (XRD). The microhardness characteristics of the obtained deposits were analyzed with dura scan hardness tester. The stability of the ceramic composite was determined using heat-treatment processes at 200 oC for 4 h. The results show that the structural behavior and corrosion resistance of the coating is dependent on the composite induced particulate and applied current density. It is found that increasing MgO contents beyond optimum level does not cause increase in microhardness progression. A decrease in applied current maximally influences the deposit adhesion characteristics. The enhanced thermal stability of 236.4 HVN for Zn- 20MgO at 0.5 A/cm2 alloy and increase corrosion behavior was thus attributed to its chemical composition, phase content and the synergistic effect of Zn and MgO on the carbon steel

Mechanical and opto-electrical response of embedded smart composite coating produced via electrodeposition technique for embedded system in defence application

The emergence of nanocomposite particulate with the increasing demand for opto-electrical properties for defence application has necessitated this study. In this work, an attempt was made to develop Zn- CeO2/Zn-CeO2-Al2SiO5 thin film composite on A356 mild steel using electrodeposition technique. The developed coating was attained in 2 V for 10 min at a constant current density of 1.5 A/cm2 and pH of 4.5. The mass concentration of Al2SiO5 was varied, ranging from 0 to 15 g. The composite coatings were characterized using Scanning electron microscope equipped with energy dispersive spectrometer (SEM/ EDS). The corroding properties of the coated and uncoated sample were examined through potentiodynamic polarization technique via Autolab PGSTAT 101 Metrohm potentiostat/galvanostat with NOVA software of version 2.1.2 in 3.65% NaCl. The electrical characterization was carried out using voltageammeter meter and Keithley 2400 series source meter application tester. The opto-electrical investigation was done using a solar simulator with maximum intensity of 1000 W/m2 under an air mass of 1.5 at a working intensity of 750 W/m2. The outcome of various test and characterizations revealed that the electrodeposited Zn-CeO2/Zn-CeO2-Al2SiO5 possessed good stability, improved microstructural qualities, better electrical conductivity and outstanding corrosion resistance