质子辐照对永磁合金微观结构演化的研究  

Effect of proton irradiation on microstructure evolution of permanent magnet

作　　者：李哲夫[1] 贾彦彦[1] 刘仁多[1] 徐玉海[1] 王光宏[1] 夏晓彬[1] 沈卫祖[1] 

机构地区：[1]中国科学院上海应用物理研究所,上海201204

出　　处：《物理学报》2018年第1期223-230,共8页Acta Physica Sinica

基　　金：上海市自然科学基金(批准号:15ZR1448500)资助的课题~~

摘　　要：钐钴和钕铁硼稀土永磁合金已经广泛应用于粒子加速器的波荡器和其他器件中,作为加速器的重要组成部分,永磁合金在辐照环境中长期服役会出现磁性能损失的现象,这会影响束流的品质.为了探讨产生这个现象的微观机理,采用透射电镜对质子辐照前后的钐钴和钕铁硼稀土永磁合金进行了微观结构演化的表征和分析,统计了由辐照析出的纳米晶体积密度和粒径分布,并讨论了微观结构演化对宏观磁性能损失的影响.结果表明,随着质子辐照损伤程度的增加,永磁合金的微观结构从单晶结构转变为纳米晶多晶结构,且纳米晶和基体的晶体结构相同.钕铁硼的纳米晶体积密度先增大后减小,粒径分布先增大后不变;钐钴的纳米晶体积密度逐渐减小,粒径逐渐增大.在2 dpa的质子辐照损伤程度下,钕铁硼稀土永磁合金比钐钴永磁合金的非晶化趋势更明显.Nd2Fe（14）B rare earth and Sm2Co（17） type permanent magnets have been widely used in the third generation of synchronous radiation light source and free electron laser facility in undulators and other components of particle accelerators.In addition, the permanent magnets are used in the radiation treatment system for cancer as a beam line component.Compared with Sm2Co（17） type permanent magnet, Nd2Fe（14） B rare earth permanent magnet has the characteristics of large magnet energy product, rich starting materials and low price. Although its Curie point and coercive force are lower than those of Sm2Co（17） type of permanent magnet, Nd2Fe（14） B rare earth permanent magnet is still widely used.As an important part of the accelerator, the magnetic loss phenomenon appears when permanent magnet is used in long-term irradiation environments, which affects the stability and quality of the beam. Therefore, it is important to investigate the magnet demagnetization induced by photon irradiation. Recently, there have appeared many researches of the phenomena of demagnetization for the permanent magnets under the irradiation of various kinds of particles. By using different research methods and experimental conditions, single particle irradiation is performed and then the effect of irradiation on magnetic loss is investigated by comparing the macro magnetic properties（such as magnetic flux loss rate, saturation magnetization, etc.）. However, there are not any available reports on the microstructure investigations of permanent magnets after irradiation. Microstructure affects macroscopic magnetic properties. In order to discuss the microscopic demagnetization mechanism, the transmission electron microscope is used to characterize and analyze the microstructure evolutions of Sm2Co（17） type permanent magnet and Nd2Fe（14） B rare earth permanent magnet before and after proton irradiation. The evolution of the number density of nanocrystal and its size distribution induced by proton irradiation are

关 键 词：质子辐照 Nd2Fe(14)B稀土永磁合金 Sm2Co(17)型永磁合金 微观结构 

分 类 号：TG132.2[一般工业技术—材料科学与工程]