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Title:

The influence of Cr doping on the flexural strength and microstructure of Sm2Co17 type sintered permanent magnet

Author(s):

LI Yu; YU Nengjun;  LIU Bingyu;  LIU lian;  ZHANG Lin;  GE Hongliang

1.College of Materials and Chemistry, China Jiliang University, Hangzhou 310018, China 2.Mianyang Liangda Technology Innovation Service Co., Ltd,Mianyang 621000, China

Keywords:

Sm2Co17 type sintered permanent magnets; Cr doping; high flexural strength; microstructure; element distribution

CLC:

PACS:

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DOI:

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DocumentCode:

Abstract:

The Sm?Co?? type sintered permanent magnets possess excellent magnetic properties, thermal stability, and corrosion resistance. However, due to the primary 2:17R phase crystal structure having few slip systems and poor symmetry, these permanent magnets exhibit relatively low bending strength. This study investigates the effects of Cr element addition on the microstructure and bending strength of Sm(Co?.??Fe?.??Cu?.??Zr?.??)?.? sintered magnets. The research found that an appropriate amount of Cr addition can effectively enhance the bending strength of the Sm?Co?? type sintered permanent magnets. When the Cr addition is 2 wt.%, the bending strength of the magnet reaches 180.12 MPa, an increase of approximately 47.75% compared to magnets without Cr addition. Microstructure and elemental distribution analysis revealed that the Cr element is uniformly distributed within the magnet, having no significant impact on the phase composition and fracture mechanism of the magnet. However, the magnets with Cr addition formed fine irregular grains at the grain boundaries, and the size of the cellular structures within these fine grains was significantly smaller than those in magnets without Cr addition. This resulted in a fine-grain strengthening effect, improving the bending strength of the magnets. This study proposes a new method to enhance the bending strength of Sm?Co??type sintered magnets by inducing the formation of fine irregular grains and their internal fine cellular structures through the addition of Cr element, which helps optimize the performance of samarium-cobalt magnets.