摘要
Grain boundary diffusion process(GBDP)serves as a promising approach in improving magnetic properties and thermal stability of Nd FeB permanent magnets.Herein,non-heavy rare earth Pr-Zn films deposited on the magnet surface using DC-magnetron sputtering system are reported.The thermal stability and coercivity enhancement mechanism of Pr-Zn GBDP magnets were investigated.Results show that the coercivity of Pr-Zn GBDP magnet increases from 963.96 kA m^-1 to 1317.14 kA m^-1 without any remanence reduction.Notably,the demagnetization curve of Pr-Zn GBDP magnet still remains a high squareness ratio.The temperature coefficient of coercivity and anti-demagnetization ability of Pr-Zn GBDP magnet under high temperatures are improved after GBDP treatment.The well-optimized rare earth-rich(RE-rich)grain boundary phases and high effective anisotropy field of(Nd,RE)2 Fe14 B magnetic hardening layers surrounding main grains are the key factors to impact the magnetic properties and thermal stability of Nd FeB permanent magnets via GBDP treatment.
Grain boundary diffusion process（GBDP） serves as a promising approach in improving magnetic properties and thermal stability of Nd FeB permanent magnets. Herein, non-heavy rare earth Pr-Zn films deposited on the magnet surface using DC-magnetron sputtering system are reported. The thermal stability and coercivity enhancement mechanism of Pr-Zn GBDP magnets were investigated. Results show that the coercivity of Pr-Zn GBDP magnet increases from 963.96 kA m-1 to 1317.14 kA m-1 without any remanence reduction. Notably, the demagnetization curve of Pr-Zn GBDP magnet still remains a high squareness ratio. The temperature coefficient of coercivity and anti-demagnetization ability of Pr-Zn GBDP magnet under high temperatures are improved after GBDP treatment. The well-optimized rare earth-rich（RE-rich） grain boundary phases and high effective anisotropy field of（Nd,RE）2 Fe14 B magnetic hardening layers surrounding main grains are the key factors to impact the magnetic properties and thermal stability of Nd FeB permanent magnets via GBDP treatment.
基金
financially supported by the National Natural Science Foundation of China(No.51561009)
the General Program of National Natural Science Foundation of Jiangxi Province(No.20192BAB206004)
the Higher School Science and Technology Landing Project of Jiangxi Province(No.KJLD14043)
the Doctoral Start-up Foundation of Jiangxi University of Science and Technology(No.3401223391)
the China Scholarship Council(No.201703000006)for funding to visit Nanyang Technological University,Singapore.
