Enhancing the coercivity of Nd-Cu-diffused Nd-Fe-B permanent magnets by Nb-assisted grain boundary pinning

M. B. Siva Kumar; D. Prabhu; M. Sadhasivam; B. Manjusha; N. Chandrasekaran; K. G. Pradeep; G. Sundararajan; R. Gopalan

doi:10.1080/21663831.2022.2104139

Materials Research Letters (Dec 2022)

Enhancing the coercivity of Nd-Cu-diffused Nd-Fe-B permanent magnets by Nb-assisted grain boundary pinning

M. B. Siva Kumar,
D. Prabhu,
M. Sadhasivam,
B. Manjusha,
N. Chandrasekaran,
K. G. Pradeep,
G. Sundararajan,
R. Gopalan

Affiliations

M. B. Siva Kumar: Centre for Automotive Energy Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, IIT Madras Research Park, Chennai, Tamil Nadu, India
D. Prabhu: Centre for Automotive Energy Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, IIT Madras Research Park, Chennai, Tamil Nadu, India
M. Sadhasivam: Correlative Microscopy Laboratory, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
B. Manjusha: Centre for Automotive Energy Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, IIT Madras Research Park, Chennai, Tamil Nadu, India
N. Chandrasekaran: National Facility for Atom Probe Tomography, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
K. G. Pradeep: Correlative Microscopy Laboratory, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
G. Sundararajan: Centre for Automotive Energy Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, IIT Madras Research Park, Chennai, Tamil Nadu, India
R. Gopalan: Centre for Automotive Energy Materials, International Advanced Research Centre for Powder Metallurgy and New Materials, IIT Madras Research Park, Chennai, Tamil Nadu, India

DOI: https://doi.org/10.1080/21663831.2022.2104139
Journal volume & issue: Vol. 10, no. 12
pp. 780 – 787

Abstract

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We report the effect of grain boundary diffusion of the Nd-Cu eutectic phase and the influence of Nb on the microstructure and magnetic properties of Nd-Fe-B melt-spun ribbons. The Atom probe tomography analysis indicated the presence of Nb clusters (∼10 nm), which possibly restricts grain growth during diffusion annealing while facilitating Nd-Cu grain boundary decoration. Correspondingly, the coercivity was enhanced from the initial 1.2 T of the as-prepared to 2.1 T for the 20 wt.% Nd-Cu diffusion annealed (600°C, 2 h). Incidentally, the as-diffused sample exhibited a high coercivity of ∼1 T at 150°C, making it suitable for high-temperature applications.

Published in Materials Research Letters

ISSN: 2166-3831 (Online)
Publisher: Taylor & Francis Group
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.tandfonline.com/journals/tmrl

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