Affiliation:
1. Materials Research Institute, Aalen University, 73430 Aalen, Germany
Abstract
The time-dependent decrease of the magnetic polarization of magnet materials in the presence of an opposing field is well known as the magnetic viscosity or magnetic aftereffect. In previous studies, magnetic viscosity was usually measured in fields when in the vicinity of coercivity HcJ, and this was conducted in order to understand the coercivity mechanism in magnetic materials. In this study, the magnetic viscosity of commercial FeNdB magnets is determined at opposing fields weaker than HcJ and at different temperatures in the range from 303 to 433 K (i.e., from 30 to 160 °C) by means of a vibrating sample magnetometer (VSM). As a result, the parameter Sv, which describes the magnetic viscosity in the material, was found to increase with increases in the opposing field. Furthermore, both the parameter Sv and its dependence on the temperature were found to correlate with the coercivity HcJ of the material. Also, a difference with regard to the parameter Sv for the materials measured in this study with similar magnetic properties, but which had undergone different types of processing, could not be found. Knowledge of the field- and temperature-dependent behavior of the magnetic viscosity of FeNdB magnets allows for better estimations over the lifetime of a component under operating conditions with respect to the magnetic losses in FeNdB magnets that are used in electric components.
Funder
German Federal Ministry of Education and Research
Subject
General Materials Science
Reference34 articles.
1. Manufacturing Processes for Permanent Magnets: Part I–Sintering and Casting;Cui;JOM,2022
2. Collocott, S.J. (2016). Reference Module in Materials Science and Materials Engineering, Elsevier.
3. Villani, M. (2018, January 12–14). High Performance Electrical Motors for Automotive Applications–Status and Future of Motors with Low Cost Permanent Magnets. Proceedings of the 8th International Conference on Magnetism and Metallurgy, Dresden, Germany.
4. Fujisaki, K. (2019). Magnetic Material for Motor Drive Systems, Springer. Engineering Materials.
5. Martienssen, W., and Warlimont, H. (2018). Springer Handbook of Materials Data, Springer International Publishing.