Iron Powder Materials Research Articles

The Influence of Rolling Processing on the Structure and Properties of Copper–Iron Powder Materials

The Influence of Rolling Processing on the Structure and Properties of Copper–Iron Powder Materials

Viscoelastic characteristic iron powder core for reducing vibration and noise radiated by switched reluctance machine

This paper presents a new direction on the mitigation of acoustic noise and vibration in a switched reluctance machine using viscoelastic property of iron powder material also known as SMC – Soft Magnetic Composite. SMC material is made of iron powder particles whose surface is insulated by an oxide layer which is continuous. With a lubricant and a binder at high pressure these particles are compacted to result a bulk material. Soft magnetic composite material is characterized by the ferromagnetic property which is isotropic and three dimensional. The reduction in eddy current loss can be attributed to the insulation coating which is tantamount to the increase in resistance in laminated core. The reduced ripple torque due to soft magnetic electrical core is because of isotropic distribution of magnetic particles. The finite element method (FEM) based simulation studies on torque ripple, vibration and noise has been described. The test results of prototype SMC-SRM, vibration and performance results have been analyzed to validate the simulation results. The study, analysis and experimentation concludes that use of SMC as core in a SRM results in reduced vibration and noise.

Development of an iron powder metallurgy soft magnetic composite core switched reluctance motor

Soft Magnetic iron powder material and electromagnetic devices based on it underwent prominent development. Basis for soft magnetic composites is tightly packed iron powder using a die into a solid material. However, the properties will in most cases be different from those obtained from compaction and machining process. This paper addresses the development of a switched reluctance machine (SRM) employing pre-form iron powder blanks (Somaloy 1000 3P) of low mass density to address the vibration and acoustic noise issues. This can be a fast and low cost approach which aim to machine the components from a pre-form blank. Finite Element Analysis (FEA) study has been conducted to determine key parameters which can be validated through experiments on the prototype motor.

The influence of sintering temperature and pressure on microstructure and mechanical properties of carbonyl iron powder materials fabricated by electric current activated sintering

In this paper, we studied the microstructure and mechanical properties of carbonyl iron powder materials fabricated by electric current activated sintering at temperatures of 650–800 °C under pressures of 20–50 MPa. All sintered samples consist of fine ferrite and spheroidized particles. The average density, average hardness and bending strength increase with an increase in either temperature or pressure. In particular, non-uniform distributions of density and hardness within the sintered samples were discussed, and a three-zone model was also proposed for simulation. Experimental and simulation results reveal that (1) the temperature distribution is homogeneous during sintering. (2) the inhomogeneous axial stress distribution, which is caused by a unidirectional load, is responsible for a poor sintering uniformity. In order to obtain homogenous sintering, more attention should be paid to axial stress distribution rather than to temperature distribution in electric current activated sintering of high thermal conductivity conductive powders like carbonyl iron powders.

Consolidation and properties of some powder materials at the example of PA-ZhGrDZ and PK10M alloys

At present, different powder materials are produced and powder products of different composition are manufactured. The most widespread are iron powder materials used in mechanical engineering. These materials are characterized by high strength combined with a high level of ductility and toughness and low tendency to brittle fracture. The properties of these materials are mainly determined by the structure formed by sintering as a result of counterdiffusion and interaction of the initial components. Upon sintering, a heterogeneous and porous structure is formed. The effect of porosity and the interpore distance on the fracture toughness is analyzed. The results of the tests prove to be consistent with the phonon theory of discrete fracture.

Experimental and computational investigation of cyclic mechanical behavior of sintered iron

Sintered metals have found wide applications in mechanical design for their low manufacturing costs. The present paper deals with a sintered iron powder material (ASC 100.29) which is specially manufactured for experimental and computational investigations. The material has been tested under both monotonic and cyclic loading conditions. Fully reversed fatigue tests have been performed with different material porosities, strain loading ratios and loading amplitudes. Cyclic stress–strain curves and corresponding fatigue life curves are identified. Experiments confirm that the cyclic loading reduces material fracture strain dramatically and the mean strain does not influence fatigue life, regardless of material porosities. The resulting hysteresis loops have been investigated concerning the hardening mechanism. The computational simulations show that the superposition of a nonlinear kinematic and isotropic hardening model can describe experiments reasonably. Computational verification reveals that the identified material model will hardly predict ratcheting behavior of the material.

Computation of the Preisach distribution function based on a measured Everett map

Modeling the hysteresis behavior of soft magnetic materials based on Preisach theory, requires a Preisach distribution function characterising the material. Although it is possible to obtain all the data for a classical Preisach model from experimental first-order curves, obtaining the Preisach distribution function by differentiating this data twice leads to large errors and even to negative values in the distribution function, This work reports on how to avoid these errors in the Preisach function when it is computed starting from measured data. Measured BH-loops are arranged into an Everett function, which is then corrected in order to serve as a basis for the Preisach distribution function. The computation method is tried out on a nonoriented, a grain oriented and an iron-powder material.

Effect of electrical resistivity on core losses in soft magnetic iron powder materials

Iron powder should be electrically insulated with a dielectric to reduce eddy current losses in components fabricated by powder metallurgy intended for AC soft magnetic applications. However, most of the dielectrics act as distributed air gaps and reduce the apparent permeability of the material. To obtain materials with good magnetic properties, the dielectric amount should then be kept as low as possible while maintaining low eddy current losses. This paper presents the influence of electrical resistivity on core losses in iron powder compacts at low frequency ( f < 1 kHz). The results obtained show that a resistivity one order of magnitude higher than the resistivity of iron (∼0.1 μΩ m) is sufficient to maintain low eddy current losses in powder cores at frequencies below 100 Hz.

Use of iron powder material for MR imaging magnet pole faces

The use of iron powder material for the pole faces of iron cored magnetic resonance imaging magnets is shown in this paper to reduce substantially the formation of eddy currents, which cause a delay in the build-up of applied gradient fields. These delays can result in errors in the computed image.

Interparticle destruction of iron powder materials : S.A.Firstov et al. Poroshkovaya Metallurgiya, No 4, 1991, 78–85, (In Russian)

Interparticle destruction of iron powder materials : S.A.Firstov et al. Poroshkovaya Metallurgiya, No 4, 1991, 78–85, (In Russian)

Interparticle failure of iron powder materials

Interparticle failure of iron powder materials

Composite Iron powder materials for the armature of axial-field permanent magnet machines

The properties of an iron powder/epoxy resin compact and its application as wedges in the armature of an axial-fleld d.c. machine are described. Compacts from carbonyl, electrolytic, and atomized iron powders are tested for their magnetic and electrical properties. Test results on carbonyl powder show that the saturation induction increases linearly with increase in the packing factor of the compact. Anisotropic behavior of compacts from electrolytic and atomized powders are investigated. Measured losses on the compacts show that for a frequency range of 200-1200 Hz, eddy-current losses are proportional to the square of frequency which shows a complete penetration of flux inside the particles. Wedges compacted from 96% atomized iron powder and 4% epoxy resin are incorporated in the armature which is tested in a machine having SmCo <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> magnets. The test results indicate that the application of the wedges reduces the circulating currents in the coils going under commutation. It was found that the magnetic losses in the wedges comprises only 2% of the total no-load losses. It was concluded that the losses introduced by the pulsating flux in the backing plate are predominant.

Effect of particle deformation on the magnetic properties of magnetic iron powder materials

1. Flake iron powders rolled with reductions of 60–80% exhibit no pronounced crystallographic texture. 2. Because of the lack of favorable texture in flake powders there is little to be gained from orienting their particles in a magnetic field during the pouring operation.

Magnetically Controlled Wave-Guide Attenuators

It has been observed that the microwave power loss of a section of wave guide filled with iron powder material could be varied by subjecting the iron powder to an externally applied magnetic field. This paper describes some experiments performed with various kinds of iron powders. Measurements have been made with the magnetic field applied parallel to, and perpendicular to the plane of the magnetic component of the electromagnetic wave inside the guide. The possibility of ferromagnetic resonance is considered. A theoretical formula for the power loss exhibited by low conductivity iron powder attenuators is developed and compared with experimental measurements.