Production method and the sintered ferrite magnet of sintered ferrite magnet

摘要

A sintered ferrite magnet comprising (a) a ferrite phase having a hexagonal M-type magnetoplumbite structure comprising Ca, an element R which is at least one of rare earth elements and indispensably includes La, an element A which is Ba and/or Sr, Fe, and Co as indispensable elements, the composition of metal elements of Ca, R, A, Fe and Co being represented by the general formula of Ca 1-x-y R x A y Fe 2n-z Co z , wherein the atomic ratios (1-x-y), x, y and z of these elements and the molar ratio n meet the relations of 0.3 ‰¤ (1-x-y) ‰¤ 0.65 , 0.2 ‰¤ x ‰¤ 0.65, 0 ‰¤ y ‰¤ 0.2, 0.03 ‰¤ z ‰¤ 0.65, and 4 ‰¤ n ‰¤ 7, and (b) a grain boundary phase indispensably containing Si, the amount of Si being more than 1% by mass and 1.8% or less by mass (calculated as SiO 2 ) based on the entire sintered ferrite magnet, and its production method.