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Abstract: Highly textured magnet powder can be produced when Nd2Fe14B alloy reacts reversibly with hydrogen at high temperature (1073K). This treatment holds promise as a production method for high-performance magnets. The appearance of anisotropy or isotropy in the magnet powder is determined by the rate of the reaction between Nd2Fe14B and hydrogen, which has been formulated in the “dynamic-hydrogenation disproportionation desorption recombination” (d-HDDR) process. The phenomena of the d-HDDR treatment are summarised in this paper including the review of the anisotropy mechanism termed here as the “texture memory effect”. [Copyright &y& Elsevier]

Presents information on a study which reported on the development of a cobalt-free neodymium iron boron anisotropic bonded magnet produced from the dynamic-hydrogenation-disproportionation-desorption-recombinatio n processed powder. Methodology; Results and discussion.

An anisotropic bonded magnet (MAGFINE2S), is about to be applied to dc motors for automobile use such as power seat motors and window motors. These dc motors have achieved a 50% reduction in weight and in volume, with the heat resistance of 120 °C. However, the heat resistance of 150 °C is required for motors near the engine, such as fan motors and wiper motors. We improved the heat resistance of the bonded magnet by the addition of Dy element to magnet powder, and succeeded in developing a bonded magnet with the heat resistance of 150 °C. [ABSTRACT FROM AUTHOR]

Abstract: Anisotropic bonded NdFeB magnets obviously have better magnetic properties than those of conventional isotropic bonded NdFeB magnets. The anisotropic bonded magnets can be used to make some magnetic devices with special oriented magnetization, such as radial oriented rings. In order to increase the magnetic properties and prolong the life of the molding die, the anisotropic bonded NdFeB magnets with radial oriented magnetization were prepared by 2-step warm compaction molding, which were called the aligning step and densifying step, respectively. In the aligning step, the magnetic powder particles aligned along the radial direction of the magnetic field (1.0T) and are compressed under 143MPa at 393K. (BH)max and density of the magnets were 146kJ/m3 and 5.7g/cm3, respectively. Then the ring compacts were re-compressed under 800MPa at 420K in the densifying step. The density increased to 6.2g/cm3 and magnetic properties were: Br=0.92 T, Hcj=1020kA/m, (BH)max =168kJ/m3. SEM micrograph showed that the magnets had excellent microstructure and the magnetic particles were evenly coated by binder. [Copyright &y& Elsevier]