成果報告書詳細
管理番号20110000000821
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 超軽量高性能モータ等向けイットリウム系複合材料の開発(3)
公開日2011/8/5
報告書年度2010 - 2010
委託先名国立大学法人名古屋大学
プロジェクト番号P08023
部署名エネルギー対策推進部
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【2】 「イットリウム系複合材料の製造工程における希少金属利用率等の効率向上
技術開発」 (2)YAG レーザPLD 法による希少金属利用率向上技術開発
(目的)YAG レーザはレーザ光の指向性が高く、空間的に均一なレーザ光が得られるため、原料ターゲットから離脱する蒸着子が形成するプルーム内の組成、エネルギー等の均一性を実現出来得る。これにより、広い面積での均一蒸着が可能となり、高い原料収率が原理的に期待できる。
(課題、解決策および目標)
現状のPLD 法においては紫外波長のエキシマレーザが主流である。それに対して市販されているYAG レーザ機器の紫外波長(4 倍波)における最大レーザエネルギーは、エキシマレーザの最大エネルギーよりも低いため、その分だけ蒸発量が低くなる可能性がある。この課題に対し、次の事項について検討した。
(i)紫外波長YAG レーザを用いたインプルーム法あるいはマルチターン/マルチパス法の採用による成膜/速度の向上
(ii)2 倍波YAG レーザの使用によるレーザエネルギーの向上。
これらの検討から、静止基板上において原料収率40%以上を実証する。また連続形成プロセスにおける原料収率40%以上の高収率技術の確立を見通すため、原料収率40%以上が達成された静止成膜結果から予想される成膜量が、移動系試料において再現できることを確認する。
英文要約Title: The Rare Metal Substitute Materials Development Project. 9-(2) Development of New Permanent Magnets Substituting for Nd-Fe-B Magnets and Development of Yttrium-based Compound. Development of Yttrium-based Composite Material for Ultra-light and High-performance Motors (FY2009-FY2011) FY2010 Annual Report (Nagoya University) [Theme 2 ” Improvement of material (Rare metals) yields in fabrication process of Y-based composite materials.” Sub-theme (2) Improvement of material yields by YAG laser PLD method] Since YAG laser has good directionality and good homogeneity of spatial distribution of the laser energy, a composition and kinetic energy of the species in the plume should become homogenous. The homogeneous deposition would lead a uniform deposition on a large area. Goal of this project is an improvement of material yield by using the pulsed laser deposition method with the YAG laser. However the PLD method using fourth harmonic YAG laser with a wave length of 266 nm has a problem. Excimer laser with a wave length of 200~400 nm is usually employed for the laser source, because of the high output energy. On the contrary, YAG laser is somewhat low output energy, total amount of ablated species would become low. To overcome this problem, we investigated following points; (i) Improvements of deposition rate and material yield by employing in-plume method and/or multi-turn system, (ii) Increase of output energy by using second harmonic YAG laser which has a wave length of 532 nm. For (i), we tried to improve the material yield of Y based superconducting films (Y-films) on small metal substrates with an area of 10×10 mm^2 which has IBAD-MgO buffer layer. To investigate an effect of in-plume method, we changed a clearance between target and substrate, and an oxygen pressure during the deposition. As a result, 19% of material yield of the Y-film on the small metal substrate was obtained by shortening the clearance and increasing the oxygen pressure. However the superconducting properties were low, Tc = 80 K and Jc=0.2 MA/cm^2 at 77 K, since the Y-film included extra Ba and Cu. From an optimization of the target composition, we obtained good superconducting film with Tc=88 K and Jc=1.8 MA/cm^2 at 77 K. We introduced a multi-turn system (3 turns) and measured a material yield on long metal tape. The material yield reached 33%. Based on the result of the small substrates, it is possible to obtain >40% of material yield by optimizing the clearance and oxygen pressure. For (ii), we deposited Y based superconducting films on small metal substrate by using second harmonic YAG laser with a wave length of 532 nm. As a result, the composition of the superconducting films was Ba and Cu rich and there were many droplets on the surface. However, the films epitaxially grew and showed Tc=89 K and Jc=1.4 MA/cm^2 at 77 K. Therefore, we can expect that the second harmonic YAG laser is available for a fabrication of Y based superconducting film.
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