Sprayed-coated barium titanate nanocomposite for corrosion protection of welded galvanized steel

Abstract

The control of corrosion at welded areas of galvanized steel is important to the structural integrity and life of components in saline environments. This research is a critical assessment of effectiveness of a sprayed barium titanate (BaTiO₃) nanopowder application as a protective coating for welded galvanized carbon steel. The substrate was made as electroplating of carbon steel with zinc and arc welding, and thus BaTiO₃ nanopowder coating by spray deposition. The coating morphology and composition were examined by the X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). Electrochemical measurements in a saline environment such as open circuit potential (OCP), potentiodynamic polarization and cyclic voltammetry (CV) showed that the corrosion resistance is greatly improved for the coated specimens. The corrosion potential of the coated weld was more noble than that of the uncoated weld (E_corr = −0.617 V vs. E_corr = −1.070 V) and the corrosion current density was significantly lower (i_corr = 1.158 μA/cm² vs. i_corr = 8.001 μA/cm²) for the uncoated sample). This gives a reduction in corrosion rate of more than 85.5% which means improved barrier and passivation properties at the welded joints. This investigation confirms the BaTiO₃ nanopowder coatings as a viable and efficient method of corrosion control in industrial settings with the potential to reduce maintenance costs and prolong the operation life of galvanized steel structures.