Assessing the impact of Si3N4 composite films and process variable on the structural and corrosion improvement of structural steel used in construction industry

The construction industry is faced with challenges arising from corrosion leading to structural deformation and pitting evolution of mild steel. This involved water and salt solutions forming electrolytes resulting in corrosion products. The struggle has been to provide special; desirable properties inform of coating to offer dependable service life for mild steel. This study seeks to assess the effects of deposition time of Ni-P-Zn-Si3N4 coatings on mild steel. The coatings were developed using direct electrolytic bath technology with constant particle concentration of silicon nitrides and different time variables. The effect of the deposition time on the substrate was assessed by electrochemical study via potentiodynamic polarization. Scanning electron microscope equipped with energy dispersive spectroscopy (SEM/EDAX) and optical microscopy was used to study the surface modification on the mild steel. It was found that deposition time affected the coating film formed and the influence of incorporating the Si3N4 phase into Ni-P-Zn series was seen to cause perfect nodularity and second phase crystals, especially with Ni-P-Zn-Si3N4 nanocrystalline deposited at 10 min. This was further established by the linear and open circuit polarization with less corroded products seen at the steel interface.