Search and Control of optimal grain boundary structure in NdFeB magnetic materials by novel electron microscopy technique

采用新型电子显微镜技术对四种钕铁硼磁性材料进行了多尺度微观结构分析，主要进行了以下五方面的研究：1.钕铁硼磁性材料；与宏观磁性结构直接相关的纳米结构分析技术的发展；2 . Tb元素在经Tb蒸发处理的Nd-Fe-B烧结磁体中的作用PLD厚膜磁体中的外加元素和矫顽力，4。HDDR磁体粉末的晶界结构和覆盖度，5。氢化烧结磁体显微组织和矫顽力的变化。其中一个值得注意的结果是发现Nd2Fe14B晶粒周围存在超薄晶界非晶态（GB）相，而超薄的GB相对Nd-Fe-B磁性材料的强压产生有很大的促进作用。

Multi-scale microstructure analysis of four kinds of Nd-Fe-B magnetic materialswere investigated by novel electron microscopy technique, and the following fiveresearches were carried out : 1. Development of nanostructure analysis technique connected directly with macro-scale magnetic structure, 2. Role of Tb element in the Tb-vaporsorption treated Nd-Fe-B sintered magnet, 3. Additive elements and coercivities in the PLD thick-film magnets, 4. Grain boundary structures and coer civities in the HDDR magnet powders, 5. Changes in microstructure and coercivity in the hydrogenated sintered magnets. One of notable results is to find the existence of ultra-thin grain boundary amorphous(GB) phase surround each Nd2Fe14B grain, and the thin GB phase contributes greatly to the generation of coereivity in Nd-Fe-B magnetic materials.