Study On The High Temperature Oxidation Resistance And Carbonization Resistance Of Diffusion Aluminized Stainless Steel

In this paper stainless steel 1Cr18Ni9Ti was dipped in molten aluminum and then diffused at high temperature. The microstructures of the hot-dipped aluminized stainless steel and diffusion aluminized stainless steel were studied with optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersion analysis of X-ray (EDAX). The high-temperature oxidation tests of diffusion aluminized stainless steel and un-dip-aluminized stainless steel were carried through 900℃, 1000℃, 1100℃in different time, then the oxidation curves were obtained, based on this the high temperature oxidation resistance of diffusion aluminized stainless steel was discussed. Diffusion aluminized stainless steel and un-dip-aluminized stainless steel were carburized at 930℃in different time, and the effect of diffusion aluminized on stainless steels to high temperature carburize was analyzed by contrast the change of the two kinds sample's microstructure.The results show that dip-aluminized stainless steel has two layers: aluminized layer and transition layer Ni₂Al₃. Stainless steel after diffusion also has two diffusion layers: the inner diffusion layer and the outer diffusion layer. The inner diffused layer is composed of Fe₃Al and a few FeAl and NiAl, and the outer diffused layer is composed of FeAl and a few Fe₃Al and NiAl.From the high-temperature oxidation test, it is found that oxidation kinetics curve of diffusion aluminized stainless steel obeys the parabolic law. The liveweight gain of diffusion alummized stainless steel is lower than raw stainless steel, the oxidation resistance is remarkably improved. Diffusion aluminized stainless steel has well oxidation resistance mostly because of the forming ofα-Al₂O₃ oxide film. Theα-Al₂O₃ oxide film is very compact, and it has steady chemical property and excellent resistance of oxidation. When carburized at high temperature, the diffusion layers of diffusion aluminized stainless steel have good resistance of hot corrosion, which hinders carbon atom infiltration. So diffusion aluminized stainless steel has better performance of high temperature oxidation resistance and high temperature carbonization resistance.