Understanding the long-term corrosion behavior of neutron absorber materials in H_(3)BO_(3)solution is crucial for the materials applications in spent fuel storage.In this paper,long-term corrosion evolution for 180 d...Understanding the long-term corrosion behavior of neutron absorber materials in H_(3)BO_(3)solution is crucial for the materials applications in spent fuel storage.In this paper,long-term corrosion evolution for 180 d in relation to the structural heterogeneities of an Fe-based amorphous coating(AMC)in H_(3)BO_(3)solution at various temperatures was systematically investigated.Results indicate that the coating corrosion could be divided into three distinct stages.Initially,the corrosion resistance increased owing to the thickening and composition evolution of the passive films.Subsequently,the corrosion rate was kept almost constant in the second stage,which connected with the steady state of the passive film.Finally,the corrosion resistance of coating reduced gradually owing to the initiation and penetration of local-ized corrosion.Interestingly,it was revealed that the localized corrosion was initiated at the relatively Cr-depleted amorphous matrix in the deep pores of the coating.This could be attributed to the synergy of Cr-depletion and occlusive effect in the deep pores during long-term immersion.With the elevation of temperature,the localized corrosion was enhanced due to the accumulation of the H+in the pores to swiftly reach the critical conditions for passive film breakdown.This work provides insights into the long-term corrosion mechanism of Fe-based AMCs in H_(3)BO_(3)solution and offers meaningful contributions to the design of new corrosion resistant neutron absorbing coatings for spent fuel storage applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U1908219 and 52171163)the Key Research Program of the Chinese Academy of Sciences(NO.ZDRW-CN-2021-2-2).
文摘Understanding the long-term corrosion behavior of neutron absorber materials in H_(3)BO_(3)solution is crucial for the materials applications in spent fuel storage.In this paper,long-term corrosion evolution for 180 d in relation to the structural heterogeneities of an Fe-based amorphous coating(AMC)in H_(3)BO_(3)solution at various temperatures was systematically investigated.Results indicate that the coating corrosion could be divided into three distinct stages.Initially,the corrosion resistance increased owing to the thickening and composition evolution of the passive films.Subsequently,the corrosion rate was kept almost constant in the second stage,which connected with the steady state of the passive film.Finally,the corrosion resistance of coating reduced gradually owing to the initiation and penetration of local-ized corrosion.Interestingly,it was revealed that the localized corrosion was initiated at the relatively Cr-depleted amorphous matrix in the deep pores of the coating.This could be attributed to the synergy of Cr-depletion and occlusive effect in the deep pores during long-term immersion.With the elevation of temperature,the localized corrosion was enhanced due to the accumulation of the H+in the pores to swiftly reach the critical conditions for passive film breakdown.This work provides insights into the long-term corrosion mechanism of Fe-based AMCs in H_(3)BO_(3)solution and offers meaningful contributions to the design of new corrosion resistant neutron absorbing coatings for spent fuel storage applications.
