鐵鎳鉻合金於氯化鈉沉積鹽之高溫腐蝕

High-Temperature Corrosion of Fe-Ni -Cr Alloys with NaCl Deposit

三種沃斯田體系Fe-Ni-Cr合金（253MA、310和353MA）於850℃進行2mg/cm2氯化鈉披覆量之高溫腐蝕研究。研究結果顯示，合金之腐蝕先是以氯氧化反應為起始反應，初期氯氧化反應所釋出之氯氣，於熔鹽揮發後被侷限於初期蝕皮膜及合金substrate之間，以氯化/氧化循環反應加速材料的腐蝕。高溫腐蝕過程中，合金元素鎳呈現鈍態之特性，合金之金屬損失與鐵和鉻之總消耗量有關。以總侵蝕深度來評估Fe-Ni-Cr合金之抗蝕性，中等鎳含量之310表現最佳。

Three austenitic Fe-Ni-Cr alloys (253MA, 310 and 353MA) have been oxidized in static air at 850℃ with a deposit of 2mg/cm2 sodium chloride (NaCl). The results showed that the initial reaction for the corrosion of alloys is oxychlorination, while the chlorine (Cl2) released from initial oxychlorination accelerated the corrosion by the cyclic chlorination / oxidation. The alloying element of nickel shows noble characteristic. The metal losses of alloys are related to the total depletion amounts of iron and chromium from the substrate. According to the evaluation of the corrosion resistance of alloys from the total depth of attack, the best performance is the 310 with medium nickel content.