An investigation of Growth mechanisms of oxide ceramic coating over time
on Micro Arc Oxidation of ZM21 magnesium alloy
Micro-arc oxidation of ZM21 magnesium alloy in silicate solution at different times was
investigated in this study to know about the growth of the ceramic coating over time. MAO process
was carried out at 5mins, 10mins, and 15mins in the silicate-based aqueous electrolyte. After MAO
process, samples were characterized using X-Ray Diffractometer to find out the phases in the
coating. The morphology of the coatings formed at different times was analyzed by Scanning
electron microscope. To understand the growth of the coating over time, eddy current coating
thickness gauge was used to measure the thickness of the coatings. Potentiodynamic polarization
test was carried out in 0.1M NaCl to find out the corrosion resistance of the coatings formed over
different time. PDP results showed that coating formed at 15 min has higher corrosion resistance
and thickness compare to coatings formed at lower time.