Abstract: A magnetic armature, having an outer ring formed of a first powdered metal, the outer ring having magnetic qualities and the first powdered metal of the outer ring includes metals having poor welding characteristics; an inner ring formed of a second powdered metal and being disposed within the outer ring, the inner ring being an iron metal having good welding characteristics and the inner ring defines an inner opening for receiving a shaft for rotating the magnetic armature; wherein said outer ring and said inner ring are joined together by a sintering process and the shaft is welded to the inner ring.

Abstract: A composition of metal powder for powder metallurgy applications comprising an iron-based powder metal admixed with a minority fraction of a ferrite powder having a lesser particle-size distribution. The ferrite particles are associated with an exterior surface of the iron-based particles and, after compression molding by a powder metallurgy technique, are incorporated into the microstructural pores between adjacent particles of iron-based powder. A composite structure formed from the composition of the present invention has an improved overall permeability and overall resistivity. A binder, such as a thermoplastic polyacrylate, may be added to the admixture of iron-based and ferrite powders for promoting the association of the ferrite powder with the iron-based powder.

Abstract: A high-density stator core for use in electrodynamic devices is fabricated by the electromagnetic pressing of an iron-based powder coated with a dielectric material and methods for performing the electromagnetic pressing are disclosed. The stator core includes a yoke portion that may further include a plurality of integral poles extending either radially outward from an outer circumferential surface of the yoke portion or radially inward from an interior circumferential surface of the yoke portion. The stator core is formed as a near-net-shape compact by an electromagnetic pressing process and has an as-formed density of at least about 98% of the theoretical density.

Abstract: A high-density stator core for use in electrodynamic devices is fabricated by the electromagnetic pressing of an iron-based powder coated with a dielectric material and methods for performing the electromagnetic pressing are disclosed. The stator core includes a yoke portion that may further include a plurality of integral poles extending either radially outward from an outer circumferential surface of the yoke portion or radially inward from an interior circumferential surface of the yoke portion. The stator core is formed as a near-net-shape compact by an electromagnetic pressing process and has an as-formed density of at least about 98% of the theoretical density.

Abstract: A method of a manufacturing rotating electromagnetic component to have both soft and hard (permanent) magnet regions, in which powder technologies are used to net-shape mold the component. A soft magnet powder material and an insert or powder of a permanent magnet material are compacted to form a rotating electromagnetic body containing soft and hard magnet regions. A partial sintering operation is then performed on the body at a temperature of 1600° F. (about 870° C.) or less, preferably about 1400° F. to 1500° F. (about 760° C. and 830° C.), and most preferably at 1500° F. to at least partially fuse the soft magnet powder materials with the permanent magnet material. The soft powder component of the resulting electromagnetic body is sufficiently fused to exhibit mechanical properties comparable to a fully sintered body (i.e., sintered at 2050° F. (about 1120° C.) or more), but without degrading the magnetic properties of the hard magnet region.

Abstract: A composition of metal powder for powder metallurgy applications comprising an iron-based powder metal admixed with a minority fraction of a ferrite powder having a lesser particle-size distribution. The ferrite particles are associated with an exterior surface of the iron-based particles and, after compression molding by a powder metallurgy technique, are incorporated into the microstructural pores between adjacent particles of iron-based powder. A composite structure formed from the composition of the present invention has an improved overall permeability and overall resistivity. A binder, such as a thermoplastic polyacrylate, may be added to the admixture of iron-based and ferrite powders for promoting the association of the ferrite powder with the iron-based powder.

Abstract: A method of curing a polymeric binder onto a powdered metal after such polymer has been coated on the powdered metal but before a part is therefrom molded, thereby forming a polymer matrix-powdered metal composite material. The polymer-coated powdered metal may be cured by retaining the polymer-coated powdered metal in a fluidized bed contained within a fluidized bath (e.g. a fluid bed coater/drier apparatus) even after the coating process has terminated. The temperature of the fluidized bath may then be raised, in turn raising the temperature of the fluidized bed, thereby curing the polymer onto the coated powdered metal in situ. By keeping the polymer-coated power metal in constant motion during the curing process, the polymer-coated powdered metal particles do not agglomerate nor otherwise adhere to other coated powdered metal particles.

Abstract: Ceramic-coated powdered ferromagnetic materials for forming magnetic articles, and which maintain the mechanical and magnetic properties of the articles at high temperatures, such as during annealing to relieve stresses induced during the forming operation. The ceramic coatings are formed by one of several techniques to provide an encapsulating layer on each ferromagnetic particle. The particles are then compacted to form a solid magnetic article, which can be annealed without concern for degrading the ceramic coating.

Abstract: A method for producing high-density powder metallurgy articles formed of hard powder materials, and particularly hard ferromagnetic materials that yield powder metallurgy magnets exhibiting improved magnetic properties as compared to powder metallurgy magnets formed of pure iron. The method generally entails the use of a powder of a material that is harder than iron, and then encapsulating each particle of the powder with a layer of iron. The powder is then compacted, by which the particles are adhered together to form a powder metallurgy article. As a result of forming a sufficiently thick encapsulating layer of iron on each powder particle, the powder can be compacted to a greater density than would be possible without the encapsulating layer of iron. If a ferromagnetic material is used, the resulting magnetic article is capable of exhibiting magnetic properties superior to a substantially identical pure iron powder metallurgy magnet.

Abstract: Disclosed is a process for producing an AC cylindrical electromagnetic ignition coil core (28) comprising:filling a cylindrical holding container (20) with powdered metal;placing the filled container into an electromagnetic field and compacting, in the radial direction, the powder in the container by subjecting the powder to the electromagnetic field; andrecovering the compacted ignition coil core (28).

Abstract: A method of forming a coating on metal particles that can be used to produce powder metallurgy articles, including those for electromagnetic and structural applications. The method is generally a solution-blending process that employs a coating solution that contains a solvent and one or more particulate additives, at least one of which is a polymeric binder that is only partially soluble in the solvent. As a result, only a portion of each binder particle is dissolved in the solvent. Notably, the coating solution is free of a discrete adhesion-promoting (tackifier) additive for adhering the polymeric binder to the metal particles. Instead, each binder particle is sufficiently dissolved in the solvent to promote adhesion of the binder particles to the metal particles during mixing, so that each metal particle is encapsulated with a coating containing the polymeric binder. The particles may then be compacted to bind them together with the coating and form a solid article.

Abstract: Method of making pole segment for a Lundell-type AC generator rotor from a mixture of ferromagnetic particles and a fugitive binder where the teeth of the rotor are molded concurrently with the base of the rotor but from a mixture of particles which is different from the mixture used to mold the base. Thereafter the segment is fired to remove the binder and sinter the metal particles together.