EVALUATION OF LONG-TERM STABILITY OF ALUM INIZED STAINLESS-STEEL USEDIN MCFCS - I - EFFECT OF HEAT-TREATMENT ON CHARACTERISTICS OF ALUMINIZED COATING LAYER

To estimate a long-term degradation behavior of the aluminized stainle ss steel (310S) used in a wet-seal area in MCFCs, the effect of beat-t reatment conditions on characteristics of the coating layer was invest igated The growing rate of inner Al diffused layer increased with the temperature. However, characteristics of the diffused layer treated at more than 1073K differed from that treated up to 1023K, The surface A l concentration was decreased from 32% to 21%, in 2000h heat-treatment at 1023K. Comparing the diffusion coefficient of Al at 923K with it a t 1023K, it was found that the characteristics of the aluminized coati ng layer conducted heat-treatment for 2000h at 1023K was approximately equivalent to that used in the wet-seal area for 40000h at 923K. From the result, it seemed to be able to evaluate the long-term stability of the aluminized stainless steel by shorter period tests.