Development of corrosion-resistant hydrophobic Zn/ZnO composite coatings on steel substrates

Abstract The surface engineering technique evolved, making it easier to protect steel from harsh and corrosive environments. Corrosion is an enduring problem for steel that cannot be completely eliminated but can be reduced to the bare minimum. Traditional methods like galvanization and painting still exist, but hydrophobic coatings are efficient and mostly used to protect the steel from deterioration. In this work we have used nano composite hydrophobic coatings among Zn (galvanized), ZnO, and Zn/ZnO on steel samples to enhance efficiency and effectiveness in reducing corrosion rate. Electrodeposition techniques are used to incorporate the coating deposits. Spark emission spectroscopy and x-ray Fluorescence elemental analysis shows the composition of bare and galvanized steel. The x-ray Diffraction analysis (XRD) analysis proved that Zn/ZnO phases are present in coatings. The results of scratch test revealed that the bond strength increased in the hydro-Zn/ZnO-coated samples as compared to the Zn or Zn/ZnO-coated samples. Furthermore, Scanning Electron Microscopy (SEM) analysis revealed the formation of a new layer on the substrate’s surface, causing it to become rough and exhibiting growing nanostructure properties. The contact angle test proves the hydrophobic nature of composite coatings on the steel samples. The STA Zn/ZnO, coating shows the super hydrophobicity with the lowest corrosion rate, at 0.04 mm/area.