Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Process for producing ferrite sintered magnet and ferrite sintered magnet
A ferrite sintered magnet comprises: main-phase grains consisting of a ferrite having hexagonal M-type magnetoplumbite structure; a first grain-boundary phase present between two main-phase grains; and a second grain-boundary phase present among three or more main-phase grains. In any cross section of the magnet, the second grain-boundary phase is present in such a state that multiple small regions of the second grain -boundary phase are scattered, while the average area of the multiple small regions is less than 0.2mum2. A process for producing the ferrite sintered magnet includes subjecting a raw material powder having a composition represented by general formula Ca1-x-yLaxAyFe2n-zCoz, wherein 1-x-y, x, y, z and n fall within required ranges respectively, n represents a molar ratio, to calcination, pulverization, molding and firing, wherein: at most 1.8mass% of SiO2 and at most 2mass% of CaCO3 in terms of CaO are added to the calcined product after the calcination and before the molding; and in the firing step, the temperature rise rate in heating from 1100 DEG C to the firing temperature is adjusted to 1 to 4 DEG C/min, and the temperature drop rate in cooling from the firing temperature to 1100 DEG C is adjusted to 6 DEG C/min or more.
Process for producing ferrite sintered magnet and ferrite sintered magnet
A ferrite sintered magnet comprises: main-phase grains consisting of a ferrite having hexagonal M-type magnetoplumbite structure; a first grain-boundary phase present between two main-phase grains; and a second grain-boundary phase present among three or more main-phase grains. In any cross section of the magnet, the second grain-boundary phase is present in such a state that multiple small regions of the second grain -boundary phase are scattered, while the average area of the multiple small regions is less than 0.2mum2. A process for producing the ferrite sintered magnet includes subjecting a raw material powder having a composition represented by general formula Ca1-x-yLaxAyFe2n-zCoz, wherein 1-x-y, x, y, z and n fall within required ranges respectively, n represents a molar ratio, to calcination, pulverization, molding and firing, wherein: at most 1.8mass% of SiO2 and at most 2mass% of CaCO3 in terms of CaO are added to the calcined product after the calcination and before the molding; and in the firing step, the temperature rise rate in heating from 1100 DEG C to the firing temperature is adjusted to 1 to 4 DEG C/min, and the temperature drop rate in cooling from the firing temperature to 1100 DEG C is adjusted to 6 DEG C/min or more.
Process for producing ferrite sintered magnet and ferrite sintered magnet
KOBAYASHI YOSHINORI (Autor:in) / HOSOKAWA SEIICHI (Autor:in) / ODA ETSUSHI (Autor:in)
08.04.2015
Patent
Elektronische Ressource
Englisch
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