Fe—Mn─Al合金的腐蚀性能与钝化膜的研究

CORROSION PERFORMANCE AND PASSIVE FILM OF AN AUSTENITIC Fe-Mn-Al ALLOY

应用阳极极化及ＡＥＳ／ＸＰＳ技术，研究了Ｆｅ－３０．８Ｍｎ－８．２Ａｌ奥氏体合金在ｐＨ值为－０．８至１５．３的水溶液中的腐蚀性能，并与Ｆｅ－３０Ｍｎ合金、低碳钢、９％Ｎｉ低温钢及１Ｃｒ１３不锈钢进行对比。在所测试的水溶液中，该合金的腐蚀抗力优于低碳钢和Ｆｅ－３０Ｍｎ合金，与９％Ｎｉ钢相当，但不及１Ｃｒ１３不锈钢。Ｆｅ－３０．８Ｍｎ－８．２Ａｌ合金在１ｍｏｌ／ＬＮａ２ＳＯ个中形成的钝化膜的最表层可能为氢氧化物，而膜的主体由Ｆｅ２Ｏ３、Ｍｎ２Ｏ３及Ａｌ２Ｏ３组成。

The corrosion properties of the austenitic Fe-30.8Mn-8.2Al alloy in a series of aqueous solutions at PH -0.8 to 15.3 and the corrosion protection mechanism induced by adding Al were studied by anodic polarization technique and by AES/ XPS analysis. The corrosion behaviour of the alloy was compared with that of Fe-30Mn alloy, mild steel, cryogenic 9% Ni steel and 1Cr13 stainless steel. The addition of 30 Wt% Mn into mild steel was very detrimental to its corrosion resistance in aqueous solution. The Fe-30Mn alloy only showed passivation behaviour in NaOH solution while the anodic polarization curves of Fe-30.8Mn-8.2Al alloy exhibited a stable passiwtion region in 1M Na2SO4, 10～50% HNO3 and 10～50%NaOH solutions, but in 10% HCI and 3.5% NaCI solutions, no passivation was observed. The corrosion resistance of Fe-30.8Mn-8.2Al alloy in these aqueous solutions was comparable to that of cryogenic 9% Ni steel but inferior to that of 1Cr13 stainless steel. According to AES/XPS analyses, the outermost surfae layer and the main part of the passive film formed on the Fe-30.8Mn-Al alloy in 1M Na2SO4 solution probably consisted of the hydroxide and a capture of iron, manganess and aluminium oxides.