Microstructure and corrosion resistance of pyrolyzed Mg – ZnO thin film coatings on mild steel

Corrosion in steel structures reduces their reliability, posing serious safety hazards and leading to costly maintenance and replacements. By weakening the steel's load-bearing capacity, corrosion heightens the risk of structural failure, especially in essential infrastructure like bridges and buildings. It also visually degrades structures, lowering property values and detracting from the appearance of architectural elements. This study investigates the impact of zinc oxide and Mg-doped zinc oxide thin film coatings on the corrosion rate and morphology of mild steel. Using chemical spray pyrolysis (CSPT), thin films of ZnO and MgO were synthesized from zinc acetate and magnesium acetate precursors, respectively, and deposited on ultrasonically cleaned, preheated mild steel substrates. Scanning electron microscopy (SEM) analysis confirmed the presence of uniform, defect-free films, while energy dispersive X-ray spectroscopy (EDX) verified Zn, Mg, and O in the coatings. The coated films enhanced the mild steel's corrosion resistance, with undoped ZnO providing the most effective surface modification. • The effect of coated ZnO and Mg-doped ZnO thin films on the corrosion rate and morphology of mild steel was investigated. • Thin films of ZnO and MgO were prepared from thermal decomposition of zinc acetate and magnesium acetate precursors. • Chemical spray pyrolysis technique (CSPT) was employed as deposition method. • Scanning electron microscopy (SEM) analysis showed conformal films with no cracks. • Undoped ZnO was found to provide the best surface modification for mild steel.