低氧压预氧化对Fe-3Al-6Cr合金表面显微组织和耐蚀性影响

Effects of Low Oxygen Pressure Pre-oxidation on Surface Microstructure and Corrosion Resistance of Fe-3Al-6Cr Alloy

在950℃,10^(-23)、10^(-16)和0.2 atm.3种氧压下对Fe-3Al-6Cr合金进行了预氧化试验,时间为10 min~1200 min。并在5%Na Cl气氛中做了耐蚀性测试。结果表明:Fe-3Al-6Cr合金在950℃、10^(-23)atm.氧压下氧化得到的是(Al,Cr)_(2)O_(3)外氧化膜,在0.2 atm.氧压下获得的是Fe_(2)O_(3)与(Al,Cr)_(2)O_(3)的混合氧化层,研究结果完全符合Factsage软件的计算结果。在10^(-16)atm.氧压下,氧化10 min的外氧化物为Fe O,合金内层存在内氧化物Fe(Al,Cr)_(2)O_(4)与Fe Al化合物。随氧化时间的延长,外层氧化物变为Fe O+Fe(Al,Cr)_(2)O_(4),内氧化物为Fe(Al,Cr)_(2)O_(4)+Al_(2)O_(3)。Factsage计算出了稳定后的表面氧化物种类,但没有计算出内氧化Al_(2)O_(3)。在盐雾腐蚀测试中,Fe-3Al-6Cr合金在950℃、10^(-23)atm.氧压中氧化30~60 min制备的(Al,Cr)_(2)O_(3)氧化膜具有最好的耐蚀性。

Pre-oxidation of Fe-3 Al-6 Cr alloys under three oxygen pressures of 10^(-23),10^(-16)and 0.2 atm.at 950℃for 10 min to 1200 min was performed.Then the corrosion resistance test was done in a 5%NaCl atmosphere.Results show that the Fe-3Al-6Cr alloy was oxidized at 950℃and 10^(-23)atm.oxygen pressure to obtain(Al,Cr)_(2)O_(3)outer oxide film.Under 0.2 atm.oxygen pressure,a mixed oxide layer of Fe_(2)O_(3)and(Al,Cr)_(2)O_(3)was obtained,which was in full compliance with the calculation results of Factsage software.After 10 min of oxidation under 10^(-16)atm.oxygen pressure,the outer oxide was Fe O,and the inner layer of the alloy was Fe(Al,Cr)_(2)O_(4)oxide and Fe Al compound.With the extension of the oxidation time,the outer oxide transformed into Fe O+Fe(Al,Cr)_(2)O_(4),and the internal oxide transformed into Fe(Al,Cr)_(2)O_(4)+Al_(2)O_(3).Factsage calculated the type of surface oxide after stabilization,but did not calculate the internal oxide Al_(2)O_(3).In the salt spray corrosion test,the(Al,Cr)_(2)O_(3)oxide film formed by the Fe-3Al-6 Cr alloy annealing at 950℃and 10^(-23)atm.oxygen pressure for 30 min to 60 min had the best corrosion resistance.