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The long-term durability of mild steel components is frequently compromised by corrosion, particularly in heavy equipment and infrastructure applications. Electrodeposited cobalt alloy coatings have emerged as a promising protective solution due to their high hardness, wear resistance, and corrosion protection capability. However, the effectiveness of these coatings is highly dependent on the quality of substrate surface preparation prior to electrodeposition. This study investigates the influence of mechanical grinding and chemical pickling on the surface integrity and corrosion performance of cobalt alloy coatings deposited on mild steel substrates.

Cobalt alloy coatings were electrodeposited using a sulfate-based electrolyte bath at a controlled temperature of 50–54 °C. Prior to deposition, the steel substrates were mechanically ground using 600- and 1200-grit abrasive papers, followed by chemical pickling in 12% sulfuric acid for immersion durations of 0, 40, 50, and 60 s. The resulting coatings were characterized through Vickers hardness testing, surface roughness measurements, Scanning Electron Microscopy (SEM) for surface morphology analysis, X-ray diffraction (XRD) for phase identification, and salt spray testing to evaluate corrosion resistance.

The study is expected to demonstrate that optimized pre-treatment conditions, particularly moderate pickling durations combined with finer surface grinding, improve coating adhesion, produce more uniform microstructures, and enhance corrosion resistance while minimizing surface defects. Improved coating quality is also anticipated to contribute to higher hardness and better long-term durability of the coated substrates.