Nd_2Fe_(14)B/α-Fe/非晶Nd-Fe-B三相纳米交换耦合磁体中的结构弛豫  

STRUCTURAL RELAXATION IN Nd_2Fe_(14)B/α-Fe/ AMORPHOUS Nd-Fe-B TRI-PHASE EXCHANGE COUPLING MAGNETS

作　　者：计齐根[1] 田宗军[1] 顾本喜[1] 章建荣[1] 都有为[1] 

机构地区：[1]南京大学物理系

出　　处：《金属学报》2001年第5期463-466,共4页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划项目G1999064508;江苏省自然科学基金资助项目BJ97043

摘　　要：用旋淬法制备了Ｎｄ２Ｆｅ１４Ｂ／α－Ｆｅ基复相纳米交换耦合磁体粉末样品．发现样品由于在室温下的结构弛豫导致磁性能的较大变化．在淬态Ｎｄ－Ｆｅ－Ｂ非晶相和Ｎｄ２Ｆｅ１４Ｂ／α－Ｆｅ纳米晶共存的三相交换磁体中，其效果更为明显．而在淬态完全非晶态或晶态的单相或复相交换磁体中，结构弛豫对磁性能的影响较弱．淬态Ｎｄ１０Ｆｅ８３Ｂ６Ｉｎ磁体粉末经过在室温下置放１年时间后，内禀矫顽力Ｈｃ由刚出炉时的２９６ｋＡ／ｍ增加至３８４ｋＡ／ｍ，剩磁比ｍｒ从０．５５增至０．６２非晶相的存在为晶粒发展完备的晶界提供了可能．应力和缺陷集中的边界区域的结构弛豫和原子调整使得相邻接的相与相、晶粒与晶粒之间的结晶学相关性提高，交换耦合增强．同时完善的晶界也增强磁体的磁硬化．Ｘ射线衍射结果显示结构弛豫的最终结果使得衍射峰宽化，极有可能在晶界处形成了畸变的晶间相．而正是这种畸变的晶间相对磁性能的增强起了关键的作用．The nano-scaled Nd2Fe14B/α-Fe based exchange coupling magnets were prepared by the melt-spun technology. It was found that the structural relaxation at room temperature leads to an enhancement of both coercivity Hc and remanence rate mr of the powder samples. Such effect is stronger in tri-phase system of nanocrystalline Nd2Fe14B/α-Fe and amorphous Nd-Fe-B than in pure crystal or amorphous structures. After stored at temperature of 0-35℃ for one year, a quenched Nd10Fe83B6In sample's coercivity Hc and remanence rate mr has increased from 296 kA/m and 0.55 of the fresh powder to 384 kA/m and 0.62 of that stored respectively. The existence of the amorphous phase provides space for grains to complete their boundaries. This structural relaxation or atomic adjustment in boundary region results in enhanced crystallographic coherence and exchange coupling between adjacent grains and phases. A perfect grain boundary also results in enhanced magnetic hardening. The result of X-ray diffraction shows a distorted boundary phase which is most likely developed by the structural relaxation due to stress relief and defect elimination.

关 键 词：ND2FE14B/Α-FE 多相纳米交换耦合磁体 结构弛豫 晶间相 

分 类 号：O751[理学—晶体学] O763