Method for preparing high performance sintered neodymium-iron-boron air stream millby hydrogenation

Abstract

The method includes steps: (1) using casting technique to produce ingot of Nd-Fe-B alloy, or using quick hardening technique to produce quick hardening slices; (2) using hydrogen explosion technique or crusher to crash alloy of ingot or quick hardening slices into coarse powder; (3) through airflow grinding machine to produce fine powder from coarse powder; and mixed compressed gas from nitrogen and hydrogen is adopted by the airflow grinding machine; (4) mixing fine powder, gasoline, and antioxidant evenly by blender so as to obtain mixed powder; (5) molded blanks are pressed from mixed powder under 1.2-2.0T magnetic field; (6) molded blanks are sintered inside high vacuum sintering furnace at deg.C 1050-1120 for 2-4h; and through temper of heat treatment 2-4h at deg.C 500-650 so as to produce sintered magnet. Comparing with traditional technique, the invention produces magnet with high coercive force, and fine powder in high efficiency, is suitable to batch production.

Description

technical field [0001] The invention relates to a high-performance sintered NdFeB jet mill hydrogenation preparation method. Background technique [0002] Rare earth NdFeB permanent magnets are the most magnetic permanent magnets in contemporary times. They not only have excellent characteristics such as high magnetic energy product and high cost performance, but also are easy to process into various sizes. They have been widely used in aviation, aerospace, microwave communication technology, electronic , electroacoustic, electromechanical, computing technology, automation technology, automobile industry, petrochemical industry, magnetic separation technology, instrumentation, magnetic medical technology and other devices and equipment that require permanent magnetic fields, especially suitable for the development of high performance, miniaturization, Various replacement products for lightweight. Rare earth NdFeB permanent magnet material is the most important permanent mag...

AI Technical Summary

Problems solved by technology

It is generally agreed that the particle size distribution of jet mill magnetic powder has a very important impact on the performance of the magnet, which mainly comes from the requirements of reverse magnetization and coercive force. Uniform distribution is conducive to the consistent rotation of reverse magnetization, and the particles with large distribution range Contains grains of different sizes, which have different critical magnetic fields for magnetization reversal. Such powders reverse at lower magnetic fields while others reverse at higher magnetic fields, resulting in poor squareness of demagnetization curves.