成果報告書詳細
管理番号20110000001381
タイトル*平成22年度中間年報 希少金属代替材料開発プロジェクト 希土類磁石向けディスプロシウム使用量低減技術開発(2)
公開日2011/12/13
報告書年度2010 - 2010
委託先名独立行政法人日本原子力研究開発機構
プロジェクト番号P08023
部署名電子・材料・ナノテクノロジー部
和文要約和文要約等以下本編抜粋:1. 研究開発の内容及び成果等 研究開発項目(3)「界面構造解析と保磁力発現機構解明による指導原理の獲得」 (3)~2 中性子小角散乱法による平均界面構造評価と保磁力 【独立行政法人日本原子力研究開発機構(武田全康)】【緒言】本研究開発項目では,研究開発項目(1)「結晶粒の微細化・原料粉末最適化による保磁力向上技術の開発」と研究開発項目(2)「界面ナノ構造制御による保磁力向上技術の開発」と連携し,Dyの使用量を削減した高保磁力Nd-Fe-B焼結磁石を実現するために必要な,保磁力と磁石内部の平均界面構造との相関を中性子小角散乱法によって明らかにすること,そして,そこで得られた情報を研究開発項目(1)(2)に還元することを大きな目的としている.今年度は,日本原子力研究開発機構の研究用原子炉JRR-3に設置されている中性子小角散乱装置(SANS-J-II)での測定に加えて,J-PARCの物質・生命科学実験施設(MLF)に設置されている茨城県材料構造解析装置(iMATERIA)を使って測定を継続するともに,データ解析の精度を上げるために解析ソフトウエアの整備に着手した.
英文要約Nd-Fe-B magnets are useful permanent magnets utilized in many applications such as motors, HDD and mobile phones. Recently, they are used in motors of a hybrid electric vehicle (HEV) which is one of the most promising applications of Nd-Fe-B magnets. As high heat resistance and high coercivity are strongly required in HEVs, some amounts of Dy are added to Nd-Fe-B magnets. However, the natural abundance of Dy is quite low and producing countries are limited. Therefore, the development of Dy-free or Dy-less Nd-Fe-B sintered magnets with high coercivity is strongly demanded. In order to enhance the coercivity, grain refinement of microstructure in sintered magnets and the microstructural control at the interface between Nd2Fe14B and Nd-rich phases are important. Therefore, the following researches were carried out in this research.: 3. “Acquirement of a guiding principle towards the Dy-free or Dy-less high performance Nd-Fe-B sintered magnets by investigation of the origin of the coercivity with interfacial structural analysis”: We performed small-angle neutron scattering (SANS) measurements of the Nd-Fe-B sintered magnets to get information on the averaged internal inhomogeneous structure of the magnets including the interfacial structures which is the key parameter to achieve the high-coercivity Dy-free Nd-Fe-B sintered magnet. In this fiscal year, we focused on anisotropic two-dimensional (2D) SANS patterns from the Nd-Fe-B sintered magnets with different grain sizes and those sintered at different temperatures to elucidate the correlation between the nonmagnetic microstructure and the coercivity. As-sintered samples were magnetized along the easy axis before the measurements. The samples had not been experienced the low-temperature annealing process. Averaged diameters of the material powders were 1.2, and 3.0 micrometers, and the sintering temperature was varied between 920 and 1020 degrees Celsius. The coercivity of these samples was changed from 2.9 kOe to 14.8 kOe by the different sintering condition.: Anisotropic SANS patterns according to the magnetized direction were observed on a 2D neutron position sensitive detector (PSD). We found that the degree of the anisotropy correlated the coercivity of each sample. Additional SANS measurements of these samples using polarized neutrons revealed that the anisotropic SANS patterns had no magnetic origin. At the first glance, the higher coercivity seems to be realized in the sample with the higher anisotropic shape of the main phase.: It is well known that the Nd-rich phase which surrounds the main phase dominantly affects the coercivity. Therefore we have to analyze the scattering pattern taking not only the anisotropic shape of the main phase but also the state of the Nd-rich phase into consideration. Specially designed analysis software for this purpose is now under development.
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