Effect of Al and Cu Additions on Microstructure and Magnetic Properties of NdTb-FeCo-B Magnets |
| G. Sadullahoğlua, B. Altuncevahirb and O. Addemirc
aBulent Ecevit University, Department of Metallurgical and Materials Engineering, 67100 Incivez, Zonguldak, Turkey bIstanbul Technical University, Department of Physics Engineering, 34469 Maslak, Istanbul, Turkey cIstanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak, Istanbul, Turkey |
| Received: January 22, 2013; In final form: December 3, 2013 |
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| With the addition of Al and/or Cu into the NdFeB based magnet, the soft free iron phase was not observed in the cast alloys while it exists in the microstructure of the undoped NdFeB ingots. For the undoped sample, free iron disappeared after hot deformation process. Grain orientation is not good and there are deviations in the growth direction of the lamellar grains which are not perpendicular to the pressing direction. On the other hand, there is a striking change that the intergranular chemistry of Al added ingot separated into Nd-rich phase and a ternary FeNdAl composition most probably formed at the pressing temperature of 750°C. The highest remanent magnetization of 7.47 kG obtained for this sample, it might be due to the hard magnetic properties of this ternary composition. For the Al-Cu added sample, the high Hc and Br values of 7.71 kOe and 7.33 kG, respectively, can be attributed to the homogeneous distribution of the intergranular composition and good orientation of the magnetic grains by hot deformation process. |
DOI: 10.12693/APhysPolA.125.1172 PACS numbers: 75.50.Ww, 75.50.Vv, 75.50.Bb |