Production method and the sintered ferrite magnet of sintered ferrite magnet

摘要

the general formula: Ca _1-xy La _x A _y Fe _2n-z Co _{in z} , wherein the 1-xy, x, y and z, and calcining a raw material powder n satisfies the required range representing a molar ratio, grinding, molding, when fired, after calcination, prior to molding in, addition of calcined body to 1.8 mass% or less of SiO ₂ and CaO 2 mass% or less of CaCO in terms of ₃ , in the firing step, 1100 ~ firing 1 to 4 C. / min heating rate at temperatures, and by the cooling rate at the firing temperature C. to 1100 C. and. 6 C. / min or more, the main consisting of ferrite having an M-type magnetoplumbite structure hexagonal a phase and a, a first grain boundary phase present between the two main phases, three or more and a second grain boundary phase present between the main phase in any cross-section, the second grain boundary phase There have been scattered, and the average area of the second of the grain boundary phase to produce a ferrite sintered magnet is less than 0.2 m ²