Journal of Applied Physics · 1991 · 10 citations · 3 references
Natural SciencesMaterials EngineeringMaterials ScienceMagnetic MaterialsMetallic MaterialsMetallurgyCorrosion-resistant MaterialsFerrimagnetic MaterialsFerromagnetic MaterialsFerromagnetismMagnetic Properties Of SolidsMagnetism In SolidsCorrosion BehaviorFerrite MagnetsMagnetic AlloysMagnetization ReversalNdfeb MagnetsSintered MagnetsTemperature StabilityTemperature-dependent Magnetization
By simultaneous additions of Co and V or of Co and Mo the temperature stability of sintered Nd-Fe-Al-B magnets can be improved.1–3 A partial substitution of Nd by Dy increases the coercivity by 1.4 kA/cm per wt. % Dy in the alloy, which results in strong coercivities at high temperatures. At 150 °C, for instance, coercivities of about 9 kA/cm can be achieved. The magnetizing behavior is determined by nucleation of reversed domains. A complete magnetization requires a magnetizing field strength of about 25 kA/cm and does not depend on the coercive field strength. Although in Nd-Dy-Fe-Co-Mo-B magnets the Nd-rich Fe eutectic and the Nd1.1Fe4B4 boride are replaced by the Nd3Co compound and the Mo2FeB2 boride, respectively, the corrosion is similar to sintered Nd-Dy-Fe-B magnets. The corrosion rate at the 85 °C–85% relative humidity test is much more determined by the surface treatment of the magnets.
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