INVESTIGATION OF INTERACTION MECHANISMS IN MELT-QUENCHED NDFEB

Investigation of the magnetization processes in melt-quenched Nd2Fe14B materials has been made by analysis of measurements of the time depen dence of the magnetizing curves (after thermal demagnetization) and de magnetizing curves at room temperature. The quantities S (the magnetic viscosity parameter) and chi(irr)i (the intrinsic irreversible suscep tibility) have been determined for the commercially available material s MQI (isotropic, resin bonded), MQII (slightly anisotropic, hot press ed), and MQIII (anisotropic, hot formed) produced by Delco Remy, U.S. In addition deltaM(H), which compares the fraction of irreversible pro cesses occurring at a particular field in the magnetizing mode with th ose occurring at the same field in the demagnetizing mode, has been de termined as a function of internal field, and the results are interpre ted in terms of interactions between grains. From these results it is shown that although the magnetization and demagnetization behavior of these materials differ substantially, this may be attributed to differ ences in the domain structure. There is no evidence that the mechanism for hardening is different from that of the sintered materials.