Thermal Aging of NdFeB Compression Molded Magnets

E-ISSN： 1662-9752|2017|899|572-575

ISSN： 0255-5476

Source： Materials Science Forum, Vol.2017, Iss.899, 2017-08, pp. : 572-575

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Abstract

Compression moulded rare earth magnets are used in many applications, and one of them is in electrical motors, which can operate at temperatures as high as 150 °C. In high temperatures, oxidation and phase transformations may affect magnetic properties. Another issue to be considered is polymer degradation. In this paper cylindrical samples of a commercial ready-to-press raw material (MQPB+, Molycorp-Magnequench) were pressed to densities close to 5.50 g/cm³. These samples were cured (low temperature heat treatment) and thermal aged at 200 °C for 72 hours, under dynamic air. Physical characteristics (weight, dimensions and densities) and magnetic properties were measured at room temperature in a TCH2020 hysteresigraph (Globalmag). Degradation of magnetic properties was observed, and oxidation seems to be the main reason.