Abstract: A number of metal cores especially suitable for use in an electrical induction device such as a transformer are disclosed herein along with respective methods of making these cores. In accordance with each of these methods, the appropriate metal material is initially provided and thereafter formed into an unsolidified, preliminary shape. Thereafter, while the material is in its preliminary shape, it is densified, preferably by means of explosion bonding, whereby to improve its permeability and saturation field characteristics. In one embodiment, a metal material is initially provided as a continuous strip. In another embodiment, the metal material is initially provided as a number of plates and still in another, preferred embodiment, amorphous metal particulate material is utilized. In this latter embodiment, the orientation of the particulate material is controlled to further improve the permeability and saturation field characteristics of the ultimately formed core.

Abstract: New ferrite pot core type products and fabrication methods are disclosed for production and assembly of tunable-inductance magnetically-soft ferrite devices. Unitary helical threads formed within the central opening of a ferrite pot core element provide controlled axial movement of a non-threaded male tuning member, carrying a ferrite rod, to adjust the air gap between spaced center posts of an assembled pair of pot core elements. Thread matching and registry requirements are eliminated by such unitary thread means which present either helical path die means, for cutting threads in a cylindrical nonmagnetic portion of a male tuning member or, circumferentially continuous helical threads, which deform nonmagnetic protrusions uniformly distributed about the periphery of a noncircular cross section nonmagnetic portion of a male tuning member during rotation of a male tuning member within a core element central opening.

Abstract: A method of making a magnetic core for a coil so that the coil obtains a desired final inductance value. The core is introduced into the coil by partly filling the inner volume of a coil former with a soft magnetic powdery material which is subsequently maintained in the correct position by the deposition of a tough liquid material on the powdery material surface, said tough liquid material forming a cover plate after curing.

Abstract: A hot roll, for use in a xerographic, dry-release, hot roll fuser, is made by a method which adds iron-containing, magnetically permeable, particles to the elastomer as the elastomer is mixed. The particles may be pre-coated with a silane adhesive promoter. The mixed elastomer is then injected around a hollow, cylindrical aluminum core. As the elastomer sets up, in the mold, a magnetic field is applied such that the iron-containing particles migrate toward the metal core, and away from the exterior surface of the elastomer. This exterior surface will later be used to fuse xerographic toner. After the elastomer has set, its external surface is ground slightly, to produce a true circular-cylinder, but without exposing the underlying, more dense, layers of iron particle filler. As a result, the elastomer-to-core interface is mechanically strong, and yet the fusing property of the elastomer is not degraded by the presence of filler.

Abstract: A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders at a temperature higher than the transition temperature range. According to the present invention, it is possible to use a polycrystalline rare earth cobalt alloy material in the field where low Curie point ferrite has been used or where bimetals have been used for a thermal valve or a temperature controlling device.

Abstract: An electromagnetic component on the basis of a sintered, oxidic material having soft-magnetic properties obtained by compressing in a mould sintered soft-magnetic prefilled bodies, preferably having the shape of rods, in such manner that they are in contact with a part of their surfaces and filling the remaining cavities with a mixture of a synthetic resin binder with a soft-magnetic powder.

Abstract: In order to obtain a sintered oxidic permanent magnetic material with improved properties, a mixture is prepared which forms a magnet having a composition defined by the formula MeFe.sub.2.sup.2+ Fe.sub.16.sup.3+ O.sub.27, where Me is one or more of the metals barium or strontium, optionally partly replaced by clacium and/or lead. A prefired product having a ferrous iron content which corresponds to the stoichiometric ferrous content of the product composition is sintered at a temperature between 1160.degree. and 1250.degree. C. in an atmopshere having such an oxygen concentration that substantially no oxygen exchange takes place between the product and the atmosphere.

Abstract: A method for preforming magnetic drum material involves the use of a hydraulic press and sleeve which in turn compresses the material and then cuts the material into a specific shape. This process is repeated until the material builds up in the sleeve to the required charge thickness. This method has improved the molding process by eliminating air and gas voids in the molded magnetic drum.

Abstract: A method of manufacturing a sintered permanent magnetizable body essentially consisting of a ferrite of the formula MeO.6Fe.sub.2 O.sub.3, wherein Me is at least one of the metals barium, strontium and lead by adding an acid to a suspension of the powdered ferrite in a liquid which suspension is then supplied to one or more matrices of a press to form a compressed product which is then sintered. As a result of the treatment with acid, the compression time is reduced.

Abstract: A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders of a spin reorientation type ferromagnetic material at a temperature higher than the transition temperature range. A polycrystalline rare earth cobalt alloy material made in accordance with the invention can now be used in the field where low Curie point ferrite or where bimetals have been used previously for a thermal valve or a temperature controlling device.

Abstract: A process for producing roll-shaped magnets which may be used in electrophotographic copying machines or the like. At least two types of composite magnet sheets of different magnetic characteristics, each having a magnetic orientation in the thickness direction, are superposed to form a laminated body. A plurality of wedge-shaped indentations are formed in one side of the laminated body. The laminated body is then wound around a shaft so that its surface having the indentations constitutes the inner peripheral surface. A magnetization is then effected. This process conveniently permits the full magnetization of the laminated body to ensure a high quality and superior characteristic of the products, as well as a high productivity. during the mass production of such magnets.

Abstract: To permit use of less expensive iron powder material and manufacture of more complex shapes, a mixture of iron powder, of an approximate grain size of between 30 to 450 .mu.m, and containing preferably 5 to 50% of carbonyl iron powder or from 5 to 50%, by weight, of soft ferrite powder of a grain size of from 10 to 200 .mu.m, and a thermosetting resin, in which the thermosetting resin is about 50% by volume of the overall mixture, is filled into a die. Pressure is built up in the die, which is heated, permitting excess binder to escape during the build-up phase thereof, the pressure then being held so that the resin can set in the heated die. The pressures needed are substantially less than heretofore required, in the order of from between 500 to 5000 bar.

Abstract: A magnetic head for magnetic tape recording and reproducing apparatus utilizing Mn-Zn single crystalline ferrite at least for the tip core or front portion of a head core where an air gap is formed, wherein different phases are locally precipitated only at the region including the air gap at the central portion thereof where a running magnetic tape contacts during the recording and reproducing operation of the apparatus. The output of the head is considerably increased with the ferrite noise inherent in single crystalline ferrite heads kept at a low level, in comparison with the conventional single crystalline ferrite heads in which the precipitation of the different phases is not limited to the above-noted region of the head core. The head is made by a method comprising disposing a masking film or coating of metal or oxide over the whole surfaces of the head core except for the above-mentioned region and treating the core at a temperature of 1,000.degree. C.-1,200.degree. C.

Abstract: Matrix-bonded permanent magnet comprising anisotropic magnet particles which have an alignment exceeding 90%. The binder is a mixture of an amorphous hot-melt polyamide resin and a processing additive which is a cyclic nitrile derivative of a saturated fatty acid dimer.

Abstract: A method of making compact cores for use in direct current magnetic apparatus characterized by the steps of severing particles from thin, flat strips of ferrous alloys, said particles being substantially of elongated rectangular shape, annealing said laminations in decarburizing and deoxidizing atmosphere to improve the magnetic characteristics by reducing carbon to less than 0.01% and relieving stresses, compressing the particles into a solidified configuration of the desired core component, and annealing the core component at a temperature upwards of 2200.degree. F. in a non-oxidizing atmosphere to improve the permeability and coercive force values.

Abstract: A method of making pressed magnetic core components characterized by coating particles of annealed low carbon ferrous alloy with a coating of hydrated magnesium silicate.

Abstract: A ferrite for magnetostrictrive vibrators is produced by the simple process of press forming a preformed structure formed from starting powder of magnetite or a mixture of magnetite and ferric oxide, said powder having an average particle size d (.mu.) of from 0.02 to 5.0 .mu., sintering this structure in an atmosphere wherein the partial pressure of oxygen is from 10.sup.-1 to 10.sup.-11 atmosphere at a temperature of from 1,000.degree. to 1,350.degree. C. and which will meet the requirement:140 log d+1,305.gtoreq.T(.degree.C.).gtoreq.160 log d+1,180and thereafter cooling the structure thus sintered to room temperature at a cooling rate m (.degree.C./min.) <0.5f where f(KHz) is a corresponding resonance frequency thereby to produce a macroscopically homogeneous ferrite structure containing as its principal constituent a sintered magnetite having an oxygen/iron (O/Fe) atomic ratio of 4.0/3<0/Fe<4.1/3, and a density of at least 90% of the theoretical density.

Abstract: Manufacturing process for ferrimagnetic materials and pressure compacted soft ferrite components utilizing a "wet" process for compositional preparation of materials in which metal carbonates and metal hydroxides are coprecipitated in controllably selected ratios.An aqueous solution of metal ions is formed by dissolving pure metals in acid. This aqueous metal ion solution is added to a predetermined solution of carbonate ions and hydroxide ions. Concentrations, temperature, and rates of addition are controlled to select the ratio of carbonate groups to hydroxide groups in the coprecipitated particles and the size of such particles.The controllably selected ratio of carbonate groups to hydroxide groups facilitates separation of the coprecipitation particles and maintains residual hydroxide groups in the material so as to extend solid-state reactivity of the coprecipitated particles for grain growth and densification purposes until the final heat treatment in which the pressure compacted articles are sintered.

Abstract: A multiple-stage sintering process is described for making low porosity manganese-zinc ferrites having good magnetic characteristics.

Abstract: Oriented strontium ferrites which yield superior ceramic permanent magnets are produced by the four-step process ofA. preparing small particles of agglomerated less than 0.1 micron grains of ferric oxide and strontium oxide,B. maintaining the particles of agglomerated oxides at temperatures of from about 800.degree. C to 1100.degree. C for up to about 24 hours to cause the oxides to react (ferritize) and form less than 0.5 micron diameter crystallites of strontium ferrite,C. sintering the crystallites into a solid body either by maintaining them at from 1100.degree. C to 1300.degree. C for not more than two hours, or preferably by maintaining them at from 800.degree. C to 1300.degree. C while applying pressure, andD. hot forging the body by applying pressures of up to about 30,000 psi at temperatures of from 800.degree. C to 1300.degree. C.

Abstract: A method is provided which comprises preparing pulverized ferrite having a magnetoplumbite type crystal structure of hexagonal system, mixing and kneading the ferrite with a viscous binding agent, subjecting the mixture to rolling to form a sheet-like mass with the easy axis being orientated in the direction perpendicular to the plane of the ferrite sheet by making use of anisotropic configuration of the crystal grains of the pulverized ferrite, rolling the sheet-like mass into a desired shape, and sintering and magnetizing the shaped ferrite.

Abstract: A method of manufacturing a formed, ferromagnetic object, particularly an annular memory core, in which a quantity of ferrite powder, a ferrite sol and a polymerized, organic compound are mixed to form an aqueous solution, which is poured out in a thin layer. A solid, elastic gel is formed, from which rings can be punched, which, after sintering, can be used as cores for memories.

Abstract: A method of improving the magnetic properties of cobalt substituted magnetite by magnetizing the material to the saturation level in the desired direction, and then removing the magnetizing field. The material will retain a level of magnetization normally referred to as the remanent state of magnetization or simply remanence. The magnetized material is then subjected to a heat treatment to anneal the material. The above process significantly improves coercivity, hysteresis loop squareness ratio, and resistance to remanence loss due to external forces.

Abstract: The small dimension (inferior to one micrometer) of the grains of oxydes obtained by chemical precipitation is retained during the processing of the ferrimagnetic part through precise stoichiometry, cold isostatic pressing and sintering under vacuum at a temperature below 1400.degree.C and for a duration shorter than 4 hours.

Abstract: There is disclosed a magnetic core and the method of making the same. The core is formed of a plurality of microlaminations. Since each discrete microlamination is of elongated rectangular shape, soft, ductile and magnetically insulated, the cores exhibit improved permeability, lower core loss, lower exciting volt amps and exhibit improved high frequency characteristics.

Abstract: Magnets are produced by dissolving in a solvent organic polymer which is a binder for magnetic powder, adding a magnetic powder to the solution, then adding to the solution a vehicle in which the polymer is insoluble. The vehicle is added until the polymer has precipitated onto the magnetic particles. These coated particles are then dried and hot pressed within an orienting magnetic field to produce the magnet.