Development of a Strong Magnets with the high anisotropy by using HDDR and micro alloying process

本研究的主要目的是阐明少量添加剂对Nd_2Fe_<14>B基磁体在氢化、歧化、脱附和结晶（HDDR）过程中磁各向异性增强的作用。通过本研究项目得到以下结果：1）Nd_<12.5>Fe_<bal>Ga_<0.3>Nb_<0.2>B<6.2>_中的Nb在铸态下形成FeNbB化合物，并通过HDDR过程稳定; 2）Nd_<12.5>Fe_<bal>Ga_<0.3>Nb_<0.2>B_<6.2>中的Ga在均匀化状态下优先占据Fe（4c）位，在结晶状态下向bcc Fe转移; 3）在复合阶段开始时，Nd_2Fe_<14>B优先在包含Ga的位置形成。结果表明，Ga主要存在于晶界附近的bcc结构Fe中，Nd_2Fe_ B的复合<14>开始于Ga存在的晶界处; 5）电弧熔炼制备的Nd_<12.5>Fe_<bal>Zr_<0.5>B_6中的Zr主要形成Zr B化合物，且这种Zr B化合物在HDDR过程中是稳定的; 6）快淬Nd_<12.5>Fe_<bal>Zr_ B_6中Zr的<0.5>位置偏好与电弧熔炼制备的样品不同，快淬Nd_<12.5>Fe_<bal>Zr_<0.5>B_6中Zr占据Nd（4f）位而不是Zr在Zr B中的位置。

The main aim of this study is to elucidate the role of small additives on the enhancement of magnetic anisotropy of Nd_2Fe_<14>B based magnets during Hydrogenation, Disproportionation, Desorption and Recombination (HDDR) process.The following results are obtained through this researching project.1) Nb in Nd_<12.5>Fe_<bal>Ga_<0.3>Nb_<0.2>B_<6.2> forms FeNbB compound in the as-cast state and it is stable through HDDR process.2) Ga in Nd_<12.5>Fe_<bal>Ga_<0.3>Nb_<0.2>B_<6.2> preferentially occupies Fe(4c) site at the homogenized state and transfers to bcc Fe at the disproportionated state.3) At the beginning of recombination stage, Nd_2Fe_<14>B forms preferentially at the place where Ga is included.4) From this result we can infer that Ga is included in bcc Fe near the grain boundary region and the recombination of Nd_2Fe_<14>B start from the grain boundary where Ga is included.5) Zr in homogenized Nd_<12.5>Fe_<bal>Zr_<0.5>B_6, which is prepared by arc melting forms ZrB and this ZrB compound is stable through HDDR process.6) Site preference of Zr in a melt-quenched Nd_<12.5>Fe_<bal>Zr_<0.5>B_6 ribbon differs from the sample prepared by arc melting ; Zr in melt-quenched Nd_<12.5>Fe_<bal>Zr_<0.5>B_6 occupies Nd(4f) site rather than Zr site in ZrB for the sample prepared by arc melting.