Development of Optimum Preparation Conditions of Fe-Deficient M-Type Ca–Sr–La System Hexagonal Ferrite Magnet

Ching-Chien Huang,Tsung-Han Hsiao,Chun-Hao Chiu,Shih-Hao Lin,Yung-Hsiung Hung,Yen-Hua Tai,Chin-Chieh Mo,H.-H Hsu,C.-H Cheng

doi:10.1109/tmag.2020.3042095

Abstract

In this work, an experiment was carried out to investigate the preparation condition of anisotropic Fe-deficient M-type Ca–Sr–La system ferrite with optimum magnetic and physical properties using the raw material Fe 2 O 3 from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {Ca}}_{1-x-y}$ </tex-math></inline-formula> La x Sr y Fe 10.9 Co z O 19 , where M-type single-phase calcined powder was synthesized with a composition of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x = 0.45$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y = 0.18$ </tex-math></inline-formula> , and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$z= 0$ </tex-math></inline-formula> . The effect of CaO, SiO 2 , and Co 3 O 4 inter-additives on the Ca–Sr–La system ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$B_{r} = 4570$ </tex-math></inline-formula> Gauss, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{b}H_{c} = 4320$ </tex-math></inline-formula> Oe, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{i}H_{c} = 5260$ </tex-math></inline-formula> Oe, and ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$BH$ </tex-math></inline-formula> ) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {max}}= 5.16$ </tex-math></inline-formula> MGOe were obtained for Ca–Sr–La system hard magnets with low cobalt content at 1.85 wt%. The magnetic properties of the prepared magnets really good compared to that of the traditional Sr–La–cobalt (Co) M-type ferrite, which has been the highest grade M-type hard ferrite. The remarkable steel industrial iron oxide waste Fe 2 O 3 is recycled to produce high-end permanent magnets under an output power of < 1 kW, which will eventually be used in high-efficiency motors.

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