K_2SO_4-Na_2SO_4沉积引起的Fe-Cr合金的低温热腐蚀  

K_2SO_4-Na_2SO_4 INDUCED LOW TEMPERATURE HOT CORROSION OF Fe-Cr ALLOYS

作　　者：张允书 李选明[1] 史良权[1] 石声泰[1] 

机构地区：[1]中国科学院上海冶金研究所

出　　处：《中国腐蚀与防护学报》1991年第1期17-26,共10页Journal of Chinese Society For Corrosion and Protection

基　　金：中国科学院腐蚀科学开放研究实验室课题;国家基金委资助

摘　　要：研究了 Fe—Cr 合金在有 K2SO_4-Na_2SO_4盐膜存在时的低温热腐蚀行为。测定涂盐的 Fe-Cr合金于 O_2-0.1、0.5和1.0%(SO_2+SO_3)气氛中在560～750℃温度区间腐蚀动力学曲线,并对腐蚀产物进行物理观察和化学分析。结果表明,当有 K_2SO_4-Na2SO_4盐膜存在时,铬含量低于某一临界值的 Fe—Cr 合金会发生低温热腐蚀,这归因于 K—Na—Fe 三元低熔点复合硫酸盐的形成。Fe^(3+)被认为参与了电化学阴极反应,Fe^(3+)/Fe^(2+)在熔盐层中的相对迁移将气相中 O_2和SO_3的主要还原反应移至熔盐/气相交界面进行,从而导致快速热腐蚀。铬是减轻和抑制低温热腐蚀的有效元素。Low temperature hot corrosion (LTHC)behavior of Fe-Cr alloys with 5 to 50 (wt)% of chromium in the presence of a K_2SO_4-Na_2SO_4 salt film was studied in O_2- 0.1,0.5 and 1.0% (SO_2+SO_3) gas environments in the temperature range of 560 to 750℃.Corrosion kinetics were measured gravimetrically,and corrosion product scales were physically examined and chemically analyzed.The experimental results indicate that the alloys with chromium contents below a certain critical value are subject to LTHC.The LTHC is related to the formation of a low melting complex sulfate containing K,Na and Fe.Fe^(3+) is believed to take part in the reduction reaction,and the countertransport of Fe^(3+)/Fe^(3+)carries the reduction reaction of O_2 and SO_3 to the melt/gas interface,which is responsible for the rapid corrosion.It is also indicated that the addition of chromium re- sults in higher LTHC resistance of iron base alloys.

关 键 词：铁基合金 K2SO4-Na2SO4 低温热腐蚀 

分 类 号：TG172.9[金属学及工艺—金属表面处理]