抄録
Influence of the alloying elements of Fe-Cr-Ni-Al alloys and Al diffusion coated stainless steels on the corrosion behavior in molten carbonate was investigated by the immersion test at 650°C for 1000h. Weight loss and dissolution of the alloying elements decreased with increasing the contents of Cr and Al in the alloy. Corrosion resistance was improved by a increase of a corrosion index (Cr+3Al). The concentration of Fe in the corrosion product decreased with increasing Al content in the alloy because of the formation of Al2O3 and Cr2O3 on the material. Corrosion resistance of the Al diffused stainless steels was improved by increasing Al and Cr concentration in the diffusion layer. Al diffusion treatment on stainless steels was found to be effective for the molten carbonate environment because the thickness and Al concentration in the layer remained unchanged at least up to 2, 000h by the corrosion test at 650°C.
