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 ۱۰۰۰̊C in air atmosphere at two different times of ۲۰ and ۶۰ 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, Fe۲ Al۵ has been the major phase formed on the surface of specimen before heat treatment. Following the oxidation of the coating at high temperature, Al ۲O۳ was formed on the surface of coating while Fe ۲ Al۵ transformed into FeAl and Fe ۳ Al 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 ۷۰۰ ̊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