The effects of thermal cycling on aging of Neodymium-Iron-Boron magnets

Abstract

In this paper, the effects of temperature cycling on Neodymium-Iron-Boron (NdFeB) magnet aging are investigated. An accelerated lifetime test is parameterized and performed. In order to separate the aging mechanism, the temperature limits given by the manufacturer are not exceeded and the thermal aftereffects, observed during the first cycles, are separated. 80 magnets with four different temperature indices and coatings are tested. The required heating and cooling half-cycle times are measured. It is proven than no secondary aging mechanisms distorts the results. A Coffin-Manson-type aging well known from other aging mechanisms and a logarithmic drop in remanence and coercive force is shown.