PREPARATION OF HIGH COERCIVE Sm-Fe-N PERMANENT MAGNET

摘要

Using pure Sm and Fe powders as starting materials,high coercive Sm-Fe-N mag-nets have been prepared by mechanical alloying in combination with beat treatmentand nitriding.The best result is:iHc=33.1 kA/cm（41.6 kOe）and（BH）max=98.7kJ/cm3（12.4 MGOe）.The phases formed in the specimens during mechanical alloying,crystallizing and nitriding processes were examined by X-ray diffraction technique.Themagnetic properties of the specimens were measured with the pulsed magnetometer infield up to 12 T.Experimental results show that mechanical alloying is an efficient ap-proach for preparing high coercive magnets.As an important factor for obtaining a highcoercivity,the grain sizes of magnets are about tens of nanometer.The presence of somesoft magnetic phases in the specimens leads to a neck on the demagnetization curve.