Preparation method of high-performance sintered samarium-cobalt magnet

Abstract

The invention discloses a preparation method of a high-performance sintered samarium-cobalt magnet. The preparation method comprises the following steps: 1) preparing samarium-cobalt alloy raw materials including, in percentage by weight, 20-25% of Sm, 12-25% of Fe, 2-4% of Zr and 3-8% of Cu, with the balance being Co, smelting the prepared samarium-cobalt alloy raw materials in an inert atmosphere, and conducting casting to obtain an alloy ingot; 2) sequentially subjecting the alloy ingot to mechanical crushing, medium crushing and airflow grinding under the protection of nitrogen to prepare alloy powder; 3) adding a lubricant into the alloy powder, and conducting mixing to prepare alloy magnetic powder; 4) weighing the alloy magnetic powder under the protection of nitrogen, conducting orientation forming in an open press, and then carrying out isostatic cool pressing so as to prepare a green body; and 5) subjecting the green body to sintering for densification treatment, then carrying out cooling for solution treatment, conducting rapid air-cooling to room temperature, and then successively carrying out heating, heat preservation, cooling, heat preservation and air-cooling to the room temperature so as to obtain the sintered samarium-cobalt magnet. The problems of rare earth volatilization and oxidation of the magnet are solved, emission of waste gas is reduced, and the obtained magnet is high in residual magnetism and good in uniformity.

Description

technical field [0001] The present invention relates to magnetic materials. More specifically, the present invention relates to a method for preparing a high-performance sintered samarium-cobalt magnet. Background technique [0002] Precipitation Hardening Sm 2 co 17 Type sintered permanent magnets are favored by researchers because of their excellent high-temperature magnetic properties, low temperature coefficient, good oxidation resistance and corrosion resistance. Because of its unique excellent performance Sm 2 co 17 Type sintered permanent magnets are used in various high-end motors. Permanent magnet motors have the advantages of high torque, high power density and high efficiency, and are widely used in many fields of military industry and aerospace. However, the high temperature resistance of permanent magnet materials and the electromagnetic characteristics under strong shock and vibration greatly affect In order to improve the performance of motors, SmCo perm...

AI Technical Summary

Problems solved by technology

Increasing the sintering temperature or increasing the holding time can increase the remanence of the magnet. However, a high sintering temperature will cause a large amount of volatilization and oxidation of rare earths. At the same time, a higher sintering temperature will promote the precipitation of zirconium-rich phases and the abnormal growth of grains. It leads to the deterioration of the performance of the magnet. Although the patent CN201910064865 discloses a preparation method of sintered samarium cobalt, the sintering time is still long (150 minutes), and the long-term sintering molding will still cause the volatilization and oxidation of rare earths

By reducing the entry of oxygen in the preparation process, the performance and oxygen content of the magnet can be controlled. For example, in the patent CN109148139A, the entry of oxygen is reduced by filling the ultra-high pressure argon gas (above 900MPa) during the sintering process, and then the magnet is optimized. performance, but this method will cause excessive waste of argon, and sintering under ultra-high pressure has high requirements for the safety and usability of sintering equipment, which is not conducive to industrial production

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