The corrosion behaviors of Fe-Cr alloy under three different pH values solutions with C1- and SO42- were investigated by localized electrochemical impedance spectroscopy （LEIS） measurements and the corrosion product...The corrosion behaviors of Fe-Cr alloy under three different pH values solutions with C1- and SO42- were investigated by localized electrochemical impedance spectroscopy （LEIS） measurements and the corrosion products were analyzed by laser Raman spectrometry. The results show that the high corrosion resistance of Fe-Cr Alloy is attributed to a passive film which is formed more easily when the alloy contains a large quantity of Cr element. However, its corrosion resistance varies in the solutions with different pH values, especially in the initial corrosion. The average impedance values in neutral and alkaline solution are much higher than that in acidic solution because the passive film is more likely to dissolve in the acidic condition. Moreover, the destructive effect of C1- and SO42 ions on the passive film is also demonstrated in corrosion process through the change of the impedance value with the steeping time.展开更多
Creep crack growth behavior of Fe-Cr15-Ni25 alloys with different grain boundary features has been studied.Cavities nucleate at triple junctions of grain boundaries for the single phase alloy and at grain boundary car...Creep crack growth behavior of Fe-Cr15-Ni25 alloys with different grain boundary features has been studied.Cavities nucleate at triple junctions of grain boundaries for the single phase alloy and at grain boundary carbide for the alloy with grain boundary carbide.Grain bounda- ry carbide particles are obstacles to cavity growth and coalescence,and therefore increase the creep crack growth resistance greatly.展开更多
Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer...Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer spectrum. The results show that the Fe_~60 Cr_~40 powders keep the bcc structure during milling in air and vacuum. The saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum and air decreases with the increase of the milling time up to 45 h. The decrease of saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum is due to the formation of Fe-Cr solid solution, while in air it is due to the formation of paramagnetic disorder structure and solid solution.展开更多
It is promising for metal especially ferritic stainless steel（FSS）to be used as interconnector when the solid oxide fuel cell（SOFC）is operated at temperature lower than 800℃.However,there are many challenges for ...It is promising for metal especially ferritic stainless steel（FSS）to be used as interconnector when the solid oxide fuel cell（SOFC）is operated at temperature lower than 800℃.However,there are many challenges for FSS such as anti-oxidant,poisoning to cathode and high area specific resistance（ASR）when using as SOFC interconnector.The effect of Cr content（12-30 mass%）in Fe-Cr alloys on thermal expansion coefficient（TEC）,oxidation resistance,microstructure of oxidation scale and ASR was investigated by thermo-gravimetry,scanning electron microscopy,energy dispersive spectroscopy and four-probe DC technique.The TEC of Fe-Cr alloys is（11-13）×10^（-6） K^（-1）,which excellently matches with other SOFC components.Alloys have excellent oxidation resistance when Cr content exceeds 22mass% because of the formation of chromium on the surface of alloy.The oxidation rate constants kdand ksdecrease rapidly with increasing the Cr content and then increase slowly when the Cr content is higher than 22mass%.The kinetic results indicate that Cr evaporation must be considered at high temperature for Fe-Cr alloys.After the alloys were oxidized in air at 800℃ for500 h,log（ASR/T）（Tis the absolute temperature）presents linear relationship with 1/T and the conduct activation energy is 0.6-0.8eV（Cr16-30）.Optimal Cr content is 22-26mass%considering the oxidation resistance and ASR.展开更多
基金National Natural Science Foundation of China (No. 50871021)
文摘The corrosion behaviors of Fe-Cr alloy under three different pH values solutions with C1- and SO42- were investigated by localized electrochemical impedance spectroscopy （LEIS） measurements and the corrosion products were analyzed by laser Raman spectrometry. The results show that the high corrosion resistance of Fe-Cr Alloy is attributed to a passive film which is formed more easily when the alloy contains a large quantity of Cr element. However, its corrosion resistance varies in the solutions with different pH values, especially in the initial corrosion. The average impedance values in neutral and alkaline solution are much higher than that in acidic solution because the passive film is more likely to dissolve in the acidic condition. Moreover, the destructive effect of C1- and SO42 ions on the passive film is also demonstrated in corrosion process through the change of the impedance value with the steeping time.
文摘Creep crack growth behavior of Fe-Cr15-Ni25 alloys with different grain boundary features has been studied.Cavities nucleate at triple junctions of grain boundaries for the single phase alloy and at grain boundary carbide for the alloy with grain boundary carbide.Grain bounda- ry carbide particles are obstacles to cavity growth and coalescence,and therefore increase the creep crack growth resistance greatly.
文摘Magnetic properties of nanocrystalline Fe_~60 Cr_~40 powders prepared by mechanical alloying in vacuum and air were investigated by utilizing the measurements of magnetization, X-ray diffraction, and ~ ~57 Fe Mssbauer spectrum. The results show that the Fe_~60 Cr_~40 powders keep the bcc structure during milling in air and vacuum. The saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum and air decreases with the increase of the milling time up to 45 h. The decrease of saturation magnetization of the Fe_~60 Cr_~40 powders milled in vacuum is due to the formation of Fe-Cr solid solution, while in air it is due to the formation of paramagnetic disorder structure and solid solution.
基金funded by Ministry of Science and Technology of China(2012CB215405)Fundamental Research Funds for Central Universities of China(FRF-TP-15-052A3)Chinese Postdoctoral Science Foundation(2014M560046)
文摘It is promising for metal especially ferritic stainless steel（FSS）to be used as interconnector when the solid oxide fuel cell（SOFC）is operated at temperature lower than 800℃.However,there are many challenges for FSS such as anti-oxidant,poisoning to cathode and high area specific resistance（ASR）when using as SOFC interconnector.The effect of Cr content（12-30 mass%）in Fe-Cr alloys on thermal expansion coefficient（TEC）,oxidation resistance,microstructure of oxidation scale and ASR was investigated by thermo-gravimetry,scanning electron microscopy,energy dispersive spectroscopy and four-probe DC technique.The TEC of Fe-Cr alloys is（11-13）×10^（-6） K^（-1）,which excellently matches with other SOFC components.Alloys have excellent oxidation resistance when Cr content exceeds 22mass% because of the formation of chromium on the surface of alloy.The oxidation rate constants kdand ksdecrease rapidly with increasing the Cr content and then increase slowly when the Cr content is higher than 22mass%.The kinetic results indicate that Cr evaporation must be considered at high temperature for Fe-Cr alloys.After the alloys were oxidized in air at 800℃ for500 h,log（ASR/T）（Tis the absolute temperature）presents linear relationship with 1/T and the conduct activation energy is 0.6-0.8eV（Cr16-30）.Optimal Cr content is 22-26mass%considering the oxidation resistance and ASR.
