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

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


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 Fe2O3 from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry Ca1-x-y LaxSryFe10.9CozO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.45 , y = 0.18 , and z= 0. The effect of CaO, SiO2, and Co3O4 inter-additives on the Ca-Sr-La system ferrite was also discussed in order to obtain lowerature sintered magnets. The magnetic properties of Br = 4570 Gauss, bHc = 4320 Oe, iHc = 5260 Oe, and ( BH )max= 5.16 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 Fe2O3 is recycled to produce high-end permanent magnets under an output power of < 1 kW, which will eventually be used in high-efficiency motors.

Original languageEnglish
Article number9277610
JournalIEEE Transactions on Magnetics
Issue number2
Publication statusPublished - 2021 Feb


  • By-product
  • circular economy
  • hard ferrite
  • iron oxide powder
  • magnet
  • motor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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