Temperature influence on magnetic characteristics of NdFeB permanent magnets

After the classes of hard ferrites and AlNiCo magnets, the research have promoted a new class of advanced magnetic materials based on rare earth materials, the Sm-Co and NdFeB types. These hard magnetic materials are used today as permanent magnets in a large variety of applications, due to their advantages: compact structure, light weight, small size, high energy density. Precision application as the permanent magnet synchronous motors ask the knowing about temperature influence on the performances of permanent magnets. In this paper, the temperature effect on the main parameters of NdFeB permanent magnets is investigated. The families of demagnetization curves for cylindrical samples of sintered NdFeB permanent magnets are experimentally obtained in the range of temperature from 25°C to 120°C. The set of variation coefficients with temperature are defined and determined. A synthesis on the interpretation of temperature influence on magnetic characteristics of NdFeB permanent magnets is done.