PROCEDURE FOR THE PRODUCTION OF LAMINATED PERMANENT MAGNETS

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It is an object of this invention to provide a method for manufacturing a permanent magnet whereby a permanent magnet of a desired shape, such as a small-scale, thinly shaped magnet which is optimal for a magnetic circuit used in an acceleration sensor, for example, and having any desired thickness, can be manufactured such that magnetic properties superior to those of a bonded magnet can be utilized effectively, by arriving at a method for manufacturing a fine crystal-type permanent magnet having hard magnetic properties of iHc >/= 2kOe and Br >/= 8kG by applying crystallization heat treatment to an amorphous thin strip obtained from a molten alloy of a specific composition by means of specific rapid cooling conditions, such that the average crystal grain size becomes 10 nm SIMILAR 50 nm. A thin permanent magnet of average thickness 10 mu m SIMILAR 200 mu m and having magnetic properties of iHc >/= 2 kOe, Br >/= 8 kG can be manufactured by fabricating rapidly cooled alloy thin strip of amorphous composition which has good tenacity, simple working properties and an average thickness of 10 mu m SIMILAR 200 mu m, from a molten alloy of a specific composition containing 6 at% or less of rare-earth element and 15 at% SIMILAR 30 at% of boron, by means of specific rapid cooling conditions, and then subjecting this rapidly cooled alloy thin strip, after cutting or punching to a prescribed shape, to crystallization heat treatment such that the average crystal grain size thereof becomes 10 nm SIMILAR 50 nm, and by layering together two or more of these thin permanent magnets and bonding and uniting the layered thin strips by means of an inorganic adhesive material or a resin, it is possible readily to provide a high-performance layered permanent magnet having a desired thickness and a prescribed shape, without using a method involving crushing and bonded magnet forming processes and without needing to carry out a cutting process after manufacture.