The HDDR (hydrogenation, decomposition, desorption, recombination) magnetic powders were made directly from strip casting (SC) alloy flakes without homogenizing treatment. Effects of hydrogen pressure during the disproportionation and the slow desorption stage of the HDDR process on the microstructure and magnetic properties of Nd2Fe4B magnetic powders were mainly studied. The results indicated that both the appropriate disproportionation pressure (Pd) and slow desorption pressure (Psd) are not only beneficial to the formation of anisotropy, but also beneficial to the optimization of microstructure and improvement of magnetic properties. The magnetic properties increase first and then decrease with increasing Pd and Psd. When Pd and Psd are 80kPa and 30kPa respectively, the magnetic powders are evident anisotropy, and have optimized microstructure and the best performance of remanence Br=1.26T, coercivity Hci =883.2kA/m, energy product (BH)max=222.5kJ/m3, and alignment degree of anisotropy DOA=0.85. The result confirmed that as long as the parameters of HDDR process are reasonably controlled, the anisotropic magnetic powders made directly from the SC alloy flakes without homogenizing treatment can be obtained.%采用未经均匀化热处理的SC(Strip casting)合金铸片为原料制备HDDR磁粉,着重研究了HDDR工艺的歧化阶段和缓慢脱氢阶段的氢气压强对Nd2Fe4B磁粉微结构和磁性能的影响.研究表明:合适的歧化压强(Pd)和缓慢脱氢压强(Psd)不仅有利于磁粉各向异性的获得,同时也有利于磁粉微结构的优化和磁性能的改善.磁粉的性能均随着Pd和Psd的增加先增大后减小.当Pd和Psd分别为80kPa和30kPa时,磁粉具有明显的各向异性,呈现最优化的微结构和最佳的磁性能:剩磁Br=1.26T,矫顽力Hcj=883.2kA/m,磁能积(BH)max=222.5 k J/m3,各向异性的取向度DOA=0.85.本研究证实了只要合理地调节HDDR工艺条件,采用未经均匀化热处理的SC合金铸片也可以制备各向异性的HDDR磁粉.
展开▼
