Corrosion behaviours of Fe–25Cr, Fe–25Cr–2Mn–1Si, Fe–25Cr–20Ni, 310SS, Ni–25Cr, and Ni–25Cr–2Mn–1Si (all in wt%) with and without NaCl–KCl deposits in Ar–60%CO₂–20%H₂O gas at 750 °C were studied. Without salt deposits, Fe–25Cr performed protectively, while Fe–25Cr–20Ni and Ni–25Cr underwent breakaway oxidation with multilayered scales formed. Adding alloy elements Si + Mn increased the corrosion resistance of all alloys by forming additional Mn-rich oxides and silica. Surface deposits of NaCl–KCl accelerated corrosion, forming porous Fe-rich oxide nodules for Fe–25Cr and thick, porous scales and internal oxidation zones for all other alloys. The protective effect of Si + Mn alloying disappeared in the presence of chlorides. Limited intergranular carbides were observed for all alloys in the gas-only condition. The extent of carburisation increased with the presence of chloride deposits for all Fe-based alloys, but remained unchanged for Ni-based alloys. Corrosion of these alloys at 750 °C is compared with that at 650 °C. The effect of chlorides in volatilising metals at 750 °C is discussed.

Fe–25Cr、Fe–25Cr–2Mn–1Si、Fe–25Cr–20Ni、310SS、Ni–25Cr 和 Ni–25Cr–2Mn–1Si（均以 wt% 计）在 Ar 中含有和不含 NaCl-KCl 沉积物的腐蚀行为–60%CO ₂ –20%H ₂研究了 750 °C 下的 O 气体。在没有盐沉积的情况下，Fe-25Cr 发挥了保护作用，而 Fe-25Cr-20Ni 和 Ni-25Cr 则发生了断裂氧化并形成了多层氧化皮。添加合金元素 Si + Mn 通过形成额外的富锰氧化物和二氧化硅来提高所有合金的耐腐蚀性。NaCl-KCl 的表面沉积物加速腐蚀，对 Fe-25Cr 形成多孔富铁氧化物球，对所有其他合金形成厚的多孔氧化皮和内部氧化区。Si+Mn合金化的保护作用在氯化物存在下消失。在仅气体条件下，所有合金都观察到有限的晶间碳化物。所有铁基合金的渗碳程度随着氯化物沉积物的存在而增加，但镍基合金的渗碳程度保持不变。将这些合金在 750 °C 时的腐蚀与 650 °C 时的腐蚀进行了比较。讨论了 750 °C 时氯化物对挥发金属的影响。