Nd-Fe-Ti-Zr-B系合金棒材與薄帶磁性、相變化及顯微結構之研究

Magnetic properties, phase evolution, and microstructure of Nd-Fe-Ti-Zr-B series rods and ribbons

蕭宗瀚(Siao, Zonghan)

指導教授 ： 張文成

國立中正大學/理學院/物理學系/碩士(2012年)

摘要

本實驗第一部分採用銅膜鑄造法製作直徑為1.1 mm，長度為1.6 mm之合金棒材，在合金棒材淬冷過程中，施以一平行長軸方向10 kOe磁場，探討棒材中不同冷卻速率區域受磁場作用後磁特性提升之程度差異。實驗結果顯示，磁場效應在冷卻速率最慢的區域磁石所提升磁性之程度最高，由未施磁場的Br = 5.6 kG，iHc = 5.9 kOe，(BH)max = 5.2 MGOe提升至Br = 5.5 kG，iHc = 9.1 kOe， (BH)max = 5.8 MGOe。
其次，以Nd9.5-1.5xFebal.Ti2.5Zr0.5B15+2x (x=0、1、2、3、4)合金系統。探討不同之Nd與B之比例對於直徑0.9 mm之合金棒材與銅輪轉速10 m/s下製作合金薄帶之磁性、相組成及微觀結構之影響。結果顯示棒材與薄帶皆隨著x的提高，其軟磁t-Fe3B與o-Fe3B相比率隨之增加、2:14:1相比率隨之下降，使得4πM12 kOe隨之上升、iHc隨之下降的趨勢。而當熱處理溫度提高，其t-Fe3B相之比率隨之下降，而o-Fe3B相比率隨之增加。棒材與薄帶之最佳磁特性出現於成分為Nd9.5Febal.Ti2.5Zr0.5B15，其磁特性分別為 Br = 6.1 kG、iHc = 11 kOe及(BH)max = 7.2 MGOe 及Br = 7.2 kG、iHc = 13.4 kOe及(BH)max =10 MGOe。
最後，比較Nd9.5Febai.Ti2.5Zr0.5B23與Nd6.5Y3Febai.Ti2.5Zr0.5B23合金棒材於不同直徑(0.9 - 2.5 mm)下之特性差異。結果顯示兩成分合金棒材隨尺寸提升其磁特性皆明顯下降。但添加Y之Nd6.5Y3Febai.Ti2.5Zr0.5B23合金棒材，其非晶形成能力明顯提升，當棒材直徑為2.5 mm且經750 ◦C熱處理後仍保有優異之磁性，其Br = 5.0 kG、iHc = 10.6 kOe及(BH)max = 4.7 MGOe。

關鍵字

外加磁場 ； 塊狀永磁 ； 合金棒材

並列摘要

In order to simplify the manufacturing the processes for making isotropic magnets, we adopted the copper mould casting method to fabricate Nd-Fe-B-type alloy rods. At first, the effect of external magnetic field applied solidification on the magnetic properties of Nd9.5Febal.Ti2.5Zr0.5Cr1B14.5C0.5 rods with different cooling rate has been studied. Applying external magnetic field during solidification could refine the grain size of the rods, resulting in the improvement of magnetic properties. Nevertheless, it is found that the slower the cooling rate, the larger the effect of external field on the magnetic properties enhancement of the bulk magnets is.
Second, magnetic properties, phase evolution, and microstructure of Nd9.5-1.5xFebal.Ti2.5Zr0.5B15+2x (x=0、1、2、3、4) rods and ribbons are studied. For both rods and ribbons, with increasing x, 4πM12kOe increases and iHc decreases due to the increase of the volume fraction of t-Fe3B、o-Fe3B phase and the decrease of 2:14:1 phase, while the volume fraction of t-Fe3B phase may decrease and o-Fe3B phase increase with increasing the annealing temperature. The optimal magnetic properties of Br = 6.1 kG, iHc = 11 kOe, (BH)max = 7.2 MGOe and Br = 7.2 kG, iHc = 13.4 kOe, (BH)max =10 MGOe could be obtained for Nd9.5Febal.Ti2.5Zr0.5B15 rod and ribbon, respectively.
Finally, the magnetic properties and microstructure of Nd9.5Febai.Ti2.5Zr0.5B23 and Nd6.5Y3Febai.Ti2.5Zr0.5B23 alloy with various diameters (0.9 - 2.5 mm) are compared. The magnetic properties of both series alloys are decreased with the increase of diameter, but the glass forming ability is obviously enhanced by Y addition. As a result, the rod magnet with a diameter of 2.5 mm annealed at 750 ◦C could also exhibit attractive magnetic properties arisen from its finer microstructure. The Br = 5.0 kG, iHc = 10.6 kOe, and (BH)max = 4.7 MGOe were attained for Nd6.5Y3Febai.Ti2.5Zr0.5B23 rod magnet.

並列關鍵字

Nd2Fe14B ； Bulk hard magnet

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