Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

• Autorzy: Lee M.-W. , Bae K.-H. , Lee S.-R. , Kim H.-J. , Jang T.-S.

Identyfikatory

DOI

10.1515/amm-2017-0189

• Języki publikacji: EN

Abstrakty

EN

We investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1st post annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd₂ Fe₁₄ B and grain boundary phases covering Nd₂ Fe₁₄ B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)₂Fe₁₄B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd₂O₃ phase.

Słowa kluczowe

EN

Nd-Fe-B sintered magnets; grain boundary diffusion process; low melting point element; DyCo alloy-powder diffusion

• Wydawca: Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences
• Czasopismo: Archives of Metallurgy and Materials
• Rocznik: 2017
• Tom: Vol. 62, iss. 2B
• Strony: 1263--1266
• Opis fizyczny: Bibliogr. 16 poz., rys.

Twórcy

autor

Lee M.-W.

• Dept. of Advanced Materials Engineering, Sunmoon University, Asan, Chungnam 336-708, Korea

autor

Bae K.-H.

• Dept. of Materials Science and Engineering, Korea University, Seoul 136-713, Korea

autor

Lee S.-R.

• Dept. of Materials Science and Engineering, Korea University, Seoul 136-713, Korea

autor

Kim H.-J.

• R&D Center of Jahwa Electronics Co. Ltd, Cheongwon 363-922, Korea

autor

Jang T.-S.

• Dept. of Advanced Materials Engineering, Sunmoon University, Asan, Chungnam 336-708, Korea

Bibliografia

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Uwagi

PL

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę (zadania 2017)