Patent ID: 9401235
Filing Date: 2016-07-26
CPC Classification: C01G,C01P,C04B,H01F

Claim Text:
1. A method for producing a sintered ferrite magnet comprising Ca, La, an element A (Ba and/or Sr), Fe and Co, and having a main phase composed of ferrite having a hexagonal, M-type magnetoplumbite structure, a grain boundary phase containing Si and Ca with a lower atomic ratio of La than in said main phase, and a third phase containing La, Ca, Si and Fe in such proportions that La is 8-50 atomic %, Ca is 20-45 atomic %, Si is 20-45 atomic %, and Fe is 4-20 atomic %, based on the total amount (100 atomic %) of those elements, wherein the third phase contains La at a higher atomic ratio than in said main phase, said method comprising a step of preparing a starting material powder having a metal element composition (by atomic ratio) represented by the general formula of Ca a step of calcining said starting material powder to obtain a calcined body; a step of pulverizing said calcined body to powder; a step of molding said powder to obtain a green body; and a step of sintering said green body to obtain a sintered body; more than 1% and 1.8% or less by mass of SiO