Effect of impurity phase on corrosion resistance and magnetic entropy change for LaFe_11.3Co_0.4Si_1.3C_0.15 magnetocaloric compound

胡洁^1,2，付松³，霍岩⁴，龙毅²，薛佳宁²

1. College of Continuing Education, Shijiazhuang Tiedao University2. School of Materials Science and Engineering, University of Science and Technology Beijing3. Technique R&D Center, Haier Group4. Tianjin Long March Launch Vehicle Manufacturing Co., Ltd.

摘 要：Effect of impurity phase（α-Fe phase and La-rich phase） on corrosion resistance and magnetic entropy change of LaFe_11.3Co_0.4Si_1.3C_0.15 compound was studied using scanning electron microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy techniques and magnetism testing. With the decrease of impurity phase, the corrosion resistance of LaFe_11.3Co_0.4Si_1.3C_0.15 compound was first enhanced and then slightly impaired. Corrosion resistance could be significantly improved by the decrease of α-Fe phase. However, the matrix phase was corroded if the La-rich phase as anode was too few. This caused the corrosion resistance to decrease slightly. After immersing the sample in distilled water for 15 d, –?S_max of the samples annealed for 3, 12 h, 3 and 7 d decreased about 50%, 41%, 16% and 17%, respectively.

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