Effect of CaO and SiO₂ Inter-additives on the Magnetic Properties of Ca–La–Co M–type Ferrite Sintered Magnets

Abstract

ABSTRACT

The effects of CaO and SiO₂ inter-additives on the densities, the average particle size and the magnetic properties of Ca–La–Co system ferrite anisotropic sintered magnets are discussed. The results show that the magnetization of sintered magnets having the same density decrease with an increase in the ratio of SiO₂ to CaO inter-additives while the non-magnetic material α–Fe₂O₃ is formed with an increase in the ratio. On the one hand, the coercivity H_cJ of Ca–La–Co system sintered magnets increase with an increase in the SiO₂ additive owing to the diminishing average particle size of sintered magnets. On the other hand, H_cJ of Ca–La–Co system sintered magnets decrease with an increase in the CaO inter-addition since the crystal growth of the sintered magnets occurs due to the CaO inter-addition.