Effect of high temperature oxidation on the corrosion behavior of aluminized low carbon steel in molten aluminum

Hot dip aluminizing was carried out on the low carbon steel rod under optimized conditions. The aluminized samples were further oxidized at 1000̊ C in air atmosphere at two different times of 20 and 60 minutes. Microstructure study and phase analysis were studied by scanning electron microscopy and X-ray diffraction methods, respectively. The characterization of the coating showed that, Fe2Al5 has been the major phase formed on the surface of specimen before heat treatment. Following the oxidation of the coating at high temperature, Al2O3 was formed on the surface of coating while Fe2Al5 transformed into FeAl and Fe3Al which are favorable to the hot corrosion resistance of the coating. Corrosion resistance of aluminized samples before and after heat treatment was evaluated by rotating the samples in the molten aluminum at 700̊ C for various times and the dissolution rate was determined. The obtained results showed that by oxidizing the coating at high temperature, the corrosion resistance of the samples in molten aluminum improves significantly

Keywords:

low carbon steel , hot dip aluminizing , high temperature oxidation , corrosion