Method of producing anisotropic ferrite magnet

Claim 1

A method of producing an anisotropic ferrite magnet having a radial particle orientation comprising mixing pulverized ferrite particles with an organic binder suitable for forming ferrite magnets to develop the particles in the planar direction perpendicular to the C-axis, said pulverized ferrite particles having a hexagonal crystal structure of the magnetoplumbite type and comprising a substance having the chemical composition MO:6Fe 2 O 3 in which M is Ba, Sr or Pb, said pulverized ferrite having been calcined and having a well-advanced crystal growth, rolling said mixture between calender rollers to form a ferrite sheet, said calender rollers being driven at substantially the same speed to align the particles with their easy axis oriented in a direction perpendicular to the plane of the ferrite sheet, placing said ferrite sheet in a solvent atmosphere for said ferrite sheet at about 30° 40° C, so as to yield a desired viscosity in said ferrite sheet for making said sheet integral during subsequent winding, said winding of said sheet being done convolutely and at tightly under pressure and a temperature of about 30°-90° to form a cylindrical shaped integral mass, free of air space between adjacent layers of said wound sheet which form said integral mass, wherein the starting end of said sheet has the cross section shown in FIG. 1 (c) of the drawings. Cutting said cylindrical shaped integral mass into the shape of a cylinder, sintering the cylindrically shaped ferrite mass at about 1,000° to 1,3000° C and applying a magnetic field to said sintered mass to complete said anisotropic ferrite magnet having said radial particle orientation.

Claim 2

A method of producing an anisotropic ferrite magnet having a radial particle orientation comprising mixing pulverized ferrite particles with an organic binder suitable for forming ferrite magnets to develop the particles in the planar direction perpendicular to the C-axis, said pulverized ferrite particles having a hexagonal crystal structure of the magnetoplumbite type and comprising a substance having the chemical composition MO:6Fe 2 O 3 in which M is Ba, Sr or Pb, said pulverized ferrite having been calcined and having a well-advanced crystal growth, rolling said mixture between calender rollers to form a ferrite sheet, said calender rollers being driven at substantially the same speed to align the particles with their easy axis oriented in a direction perpendicular to the plane of the ferrite sheet, placing said ferrite sheet in a solvent atmosphere for said ferrite sheet at about 30° 40° C, so as to yield a desired viscosity in said ferrite sheet for making said sheet integral during subsequent winding, said winding of said sheet being done convolutely and at tightly under pressure and a temperature of about 30°-90° to form a cylindrical shaped integral mass, free of air space between adjacent layers of said wound sheet which form said integral mass, wherein the starting end of said sheet has the cross section shown in FIG. 1 (c) of the drawings. Cutting said cylindrical shaped integral mass into the shape of a cylinder, sintering the cylindrically shaped ferrite mass at about 1,000° to 1,3000° C and applying a magnetic field to said sintered mass to complete said anisotropic ferrite magnet having said radial particle orientation.