热处理工艺对铁基软磁复合材料电磁性能的影响

Effect of heat treatment process on magnetic and electrical properties of Fe-based soft magnetic composites

以磷酸为磷化剂对雾化铁粉进行磷化处理,然后在800 MPa压力下压制成环形生坯,分别在H2、N2和空气气氛下进行热处理,制成软磁复合材料磁芯,研究热处理气氛、热处理温度与时间对磁芯电磁性能的影响。结果表明:铁粉经磷化处理后,表面包覆完整均匀的磷酸盐绝缘层;与H2和N2气氛相比,磁芯压坯在空气气氛下热处理后拥有更高的磁导率和较小的磁损耗;空气气氛下500℃处理30 min是较优的热处理工艺,磁芯最大磁导率达到350,在频率为1 k Hz和饱和磁感1T条件下的磁损耗仅为145 W/kg,进一步延长热处理时间或提高热处理温度,磁导率增加不明显,但电阻率显著降低,导致磁损耗显著增加,软磁性能恶化。

Fe-based soft magnetic composites （SMC） were fabricated using the phosphating atomized iron powders pressed at 800 MPa and then heat-treated in the atmosphere of H2, N2 and air, respectively. The effects of heat treatment atmosphere, temperature and time on the magnetic and electrical properties of the composites were studied. The results show that the iron powders surface is covered by the iron phosphate coating uniformly during the process of phosphating. High magnetic permeability and low magnetic loss are obtained after the heat treatment at the atmosphere of air. Moreover, the sample treated in air at 500~C for 30min exhibits an excellent comprehensive performance, with the maximum magnetic permeability of 350, and the minimum magnetic loss of 145 W/kg when the frequency is 1 kHz and the saturation flux density is 1T. However, increasing time or temperature of the heat treatment, there is no obvious increases of the magnetic permeability, but electrical resistivity decreases sharply, which results in magnetic loss increasing and magnetic properties worsening.