NdFeB magnet and preparation method thereof

Abstract

The invention provides an NdFeB magnet which comprises, by mass, 29% to 33% of Pr-Nd, 0.97% to 1.5% of B, 0.4% to 0.6% of Dy, 0.2% to 0.8% of Al, 0.6% to 0.8% of Co, 0.01% to 0.5% of Cu, 0.01% to 0.2% of Zr and the balance Fe. The invention further discloses a preparation method of the NdFeB magnet. The method includes the steps that firstly, Pr-Nd alloy, Zr-Fe alloy, B-Fe alloy, Dy-Fe alloy, aluminum, cobalt, copper and iron are molten to prepare an NdFeB cast ingot; secondly, the obtained NdFeB cast ingot is milled into NdFeB powder; finally, the NdFeB powder is sintered into the NdFeB magnet. The NdFeB magnet prepared through the method has a more refined magnet grain size and higher magnet stability.

Description

Technical field [0001] The invention belongs to the technical field of magnet preparation, and in particular relates to a neodymium iron boron magnet and a preparation method thereof. Background technique [0002] Magnets are materials that can generate magnetic fields and have the property of attracting ferromagnetic materials such as iron, nickel, cobalt and other metals. Magnets are generally divided into permanent magnets and soft magnets. The materials used as magnetic conductors and electromagnets are mostly soft magnets, and their polarity changes with the polarity of the applied magnetic field. Permanent magnets are hard magnets that can maintain their magnetism for a long time. , It is not easy to lose magnetism, and it is not easy to be magnetized. Therefore, whether in industrial production or in daily life, hard magnets are one of the most commonly used strong materials. [0003] Hard magnets can be divided into natural magnets and artificial magnets. Artificial magne...

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Problems solved by technology

[0005] At present, the sintering method is often used in the industry to produce NdFeB magnets. Most of the sintering furnaces for sintered NdFeB magnets are heated by thermal radiation. However, due to the limitation of the sintering process, it is easy to cause excessive sintering of the magnets and produce grains. Abnormal growth, lower magnet coercive force, or insufficient sintering of the central magnet occurs

In the prior art, the patent CN10104187A discloses a preparation process and application of a zirconium hydrogen grain growth inhibitor, which first hydrogenates zirconium into ZrH in a hydrogen furnace X , and then use the zirconium hydrogen grain growth inhibitor airflow to grind it into ultrafine powder with a particle size of less than 2 μm, which can inhibit the abnormal growth of grains. The process is complicated, which is not conducive to industrial production

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