The Influence of Aluminum Nitrate Pre-Treatment on High Temperature Oxidation Resistance of Dip-Coated Silica Coating on Galvanized Steel

• Published in: ECS transactions 2018-01, Vol.85 (2), p.67-73
• Main Authors: Yang, Tzu-Chin, Chang, Jun-Kai, Lin, Chao-Sung
• Format: Article
• Language: English
• ISSN: 1938-5862; 1938-6737; 1938-6737; 1938-5862
• DOI: 10.1149/08502.0067ecst

Hot-dip galvanizing is one of the common methods for anti-corrosion treatments on steels nowadays. However, liquid metal induced embrittlement and high temperature oxidation occur during the austenitization treatment of hot-dip galvanized press hardening steel. This present study focused on the effect of aluminum nitrate pre-treatment on the properties of the subsequent silica coating formed via sol-gel route. The high temperature oxidation resistance was evaluated using the thermal gravimetric analysis and the microstructural evolution was followed during austenitization. Experimental results showed that the silica coating with pre-treatment had better high temperature oxidation resistance and hindered the liquid phase evaporation. The Auger spectroscopy analysis further revealed that the surface of hot-dip Zn coating became chemically homogeneous after the aluminum nitrate pre-treatment, signifying the necessity of a homogeneous aluminum hydroxide surface layer to enhance the adhesion and oxidation resistance of the silica coating on hot-dip galvanized steel during austenitization.