Coercivity enhancement by low oxygen content graphene addition in hot-deformed Nd-Fe-B

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:511

Article

Yang, Qiaosen^1,3  Wang, Renquan^1,3  Liu, Ying^1,2  Li, Jun^1,2  Chen, Hongxing^1,3  Yang, Xiaojiao^1,3 

[1] Sichuan Univ, Coll Mat Sci & Engn, Chengdu 610065, Peoples R China

[2] Minist Educ, Key Lab Adv Special Mat & Technol, Chengdu 610065, Peoples R China

[3] Sichuan Univ, Rare Earth & Vanadium Titanium Mat Res Ctr, Chengdu 610065, Peoples R China

关键词: Nd-Fe-B;    Hot-deformation;    Low oxygen content graphene nanoplatelets;    Microstructure;    Coercivity;   

DOI  :  10.1016/j.jmmm.2020.166940

来源: Elsevier

【 摘 要 】

The effects of oxygen content in graphene nanoplatelets (GNPs) on the microstructure and magnetic properties of hot-deformed (HDed) Nd-Fe-B magnets were investigated in this work. The GNPs were heat treated at 500 degrees C to effectively reduce the oxygen content from 27000 ppm (GNP-R) to 7768 ppm (GNP-H). Compared with adding the same amount of GNP-R, the GNP-H doped magnet possessed finer and better texture grains at the contact interface of original powders. The coercivity of GNP-H doped magnet was enhanced from 14.16 kOe to 16.62 kOe, and the remanence increased from 13.18 kGs to 13.61 kGs. Owing to the high thermal conductivity of GNP-H doped magnet, the heat transferred between the grains more quickly and thus restraining the grain growth. Therefore, the GNP-H doped magnet got a higher coercivity. The observation of microstructure revealed that the adsorbed oxygen on the surface of GNP-R reacted with Nd-rich phase. It would result in the oxidation of Nd-rich phase and the decreasing of Nd-rich phase at the grain boundaries. Because of inadequate liquid Nd-rich phase, the Nd2Fe14B grains were difficult to complete the dissolution-reprecipitation. Consequently, a high oxygen environment would deteriorate the orientation of grains.

【 授权许可】

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