High temperature corrosion behavior of metals in HCl-containing atmosphere

摘要

High temperature corrosion behavior of Fe, Cr, Ni and their alloys was expounded from the viewpoint of thermodynamics and scale morphologies. Corrosion experiment was accomplished in 1 %HCl-50%O{sub}2-N{sub}2 atmosphere at 873-1273K by thermogravimetric technique. Metal loss curve was measured as well as mass change measurement. From the result, accelerated oxidation mechanism was discussed. Furthermore, distribution of metal loss by oxidation and by chlorination in the total metal loss was also examined. That pointed out chlorination of metal and chlorination of oxides has some incubation period. For Fe-Cr and Ni-Cr alloys, it was revealed that Cr addition is also effective to prevent chlorination of these alloys. In addition, effect of moisture in the atmosphere was examined. From all the results and discussions, it was concluded that in case of chlorine corrosion of metals physico-chemical properties of metal chloride is quite important to realize the phenomena. Finally formulization of mass change curve was attempted by computer concerning with the incubation period of chlorination of metals and oxides.