Study on Surface Coating and Properties of Q345 Steel for Building Structure

Coatings of different components on the surfaces of the steel structure were prepared by hot dipping method, and the effects of Mn content in the bath on the morphology, corrosion weight loss and oxidation weight loss of the coating were studied.The results showed that the coatings from dipping solutions with different contents of Mn were composed of delta phase (FeZn₁₀), diffuse-Δ (damage delta phase + Zn) and the coarse zeta phase (FeZn₁₃), and in the same dipping time there were no significant differences on coating thicknesses; that the coating obtained in Zn-0.5% Mn plating bath had the best corrosion resistance, followed by Zn-1.3% Mn coating, higher than that from pure Zn plating solution; that with the increase of oxidation time, the oxidation weight loss of the three kinds of coatings increased first and then decreased, and within 15 hours of oxidation, the oxidation weight losses of coatings from Zn-0.5% Mn and Zn-1.3% Mn plating solutions were significantly lower than that of coating from pure Zn plating solution at the same time.