Magnetocaloric effect， corrosion behavior and corrosion prevention of LaFe11.832-xNixSi1.4 alloy

To solve the corrosion problem of La（Fe， Si）13 magnetic refrigeration material in the heat exchange medium， an attempt is made to partially replace Fe element with Ni element. The magnetocaloric properties of LaFe11.832-xNixSi1.4（x=0，0.1，0.2，0.3，mass fraction，the same below） alloys before and after the substitution， as well as the corrosion behavior in different media， are systematically studied. The results show that when the Ni content is less than 0.2， LaFe11.832-xNixSi1.4 can maintain good magnetocaloric performance. Its magnetic entropy change under a 2 T magnetic field can reach 15.31 J/（kg·K）（x=0.1） and 14.00 J/（kg· K） （x=0.2）， and the relative magnetic cooling capacity is 151.6 J/kg and 156.8 J/kg， respectively， with significantly reduced magnetic hysteresis loss. In deionized water， the corrosion current Icorr of LaFe11.832-xNixSi1.4 alloy decreases from 2.6159 μA/cm2 to 2.0863 μA/cm2 with increasing Ni content. The maximum corrosion inhibition efficiency of LaFe11.832-xNixSi1.4 alloy in combined inhibitor of 4 g/L BTA+1 g/L Na2MoO4·2H2O is 77.06%， showing a good corrosion inhibition effect. The LaFe11.832-xNixSi1.4（x≤0.2） alloy with 4 g/L BTA+1 g/L Na2MoO4·2H2O can be used as an alternative combination of working fluid and medium for practical magnetic refrigerators.