Papers by Keyword: Iron Powder

Abstract: This study presents the synthesis of carbon composites based on iron powder and hydrolysis lignin, both with and without the addition of oleic acid. The synthesized composites were characterized using X-ray diffraction, gas adsorption-desorption porosimetry, and magnetometry. In addition, the adsorption performance of the composites toward methylene blue and congo red dyes from aqueous solutions was investigated. It was found that the addition of oleic acid does not significantly alter the structural or magnetic properties of the synthesized composite. However, it does affect the composition of oxygen-containing surface groups on the carbon. Analysis of the adsorption isotherms revealed that the carbon composite synthesized with oleic acid is nearly equally effective in adsorbing both methylene blue and congo red dyes. Isotherm modeling demonstrated that the synthesized composites adsorb both dyes via a physisorption mechanism.

Abstract: Iron and iron-phosphorus open-cell foams were tested for their potential use as synthetic bone graft substitutes. The samples were manufactured using a replica method based on a powder metallurgical approach. Iron foams alloyed with 0.5 wt. % of phosphorus were prepared with the aim of enhancing the mechanical properties and manipulating the corrosion rate. The manufactured foams were tested for their microstructure, porosity, corrosion behaviour and mechanical properties. SEM analyses of the foams’ microstructures confirmed the presence of an open, three-dimensional interconnected macroporous network similar to that of the human bone. The corrosion behaviour was studied by a static immersion test and potentiodynamic polarisation in Hank’s solution. The results showed that the presence of phosphorus slightly decreased the corrosion rate as compared to pure iron foams. The mechanical properties studied by a compression test confirmed a positive effect of phosphorus on the mechanical properties of the manufactured foams.

Abstract: The paper presents a new technological scheme for obtaining bimetallic materials of the composition "aluminum casting alloy - sintered iron powder" by the method of joint stamping. The results of experimental studies of the effect of process conditions on the physicomechanical properties of the starting materials and the adhesive strength of the final bimetal blank are presented.

Abstract: Highly oxidized iron powders were consolidated by means of the medium-frequency electrical resistance sintering technique (MF-ERS). In order to activate the powders and to disperse the oxides coating the particles, prior to the consolidation process, powders were milled in a high-energy mill for 7 minutes. Structural and mechanical characterisations of electrically consolidated compacts were carried out in order to study the effect of two main processing parameters (current intensity and heating time). The compact properties resulted to be very sensitive to these parameters, especially to the current intensity. A change from 5 kA to 10 kA in the current intensity makes the porosity to fall from 30% to 8%. Moreover, using a higher current intensity (10 kA) increases the mechanical properties of the final compacts: micro-hardness change in almost 50 HV, up to 104 HV 1, and compression resistance by around 500 MPa, up to 569 MPa.

Abstract: A new technology of metal billets production by molding and thermal treatment of compositions based on iron powders of medium dispersion, fine powders of iron oxide, and the thermosetting binder, which provides for the required physical and mechanical properties of the material, is proposed. It is found that, at a certain concentration and dispersion of the components of the solid phase, the injection and direct compression molding of parts of complex shape (similar to the MIM-technology) is possible at pressures from 70 MPa to 100 MPa ensuring uniform density over the cross section. The established stages of thermal treatment of compositions, thermal behavior and protective medium ensuring uniformity of products, and chemical composition of the product material are presented in the paper. The experimental and theoretical studies of the dimensional accuracy of steel products obtained by the developed technology were carried out, and it was discovered that the produced parts were of the precision of steel parts produced by MIM-technology.

Abstract: Stable finishing is considered difficult to achieve using conventional magnetic abrasive because of its unstable polishing characteristics. In this paper, three different shapes of iron particles are used to produce a magnetic brush to improve stability. The unsteady and steady polishing force produced under the magnetic field of an end-mill type tool is discussed. We also develop prototype equipment combining a high speed camera with a force sensor to analyse micro-changes in the magnetic brush while machining. The relationship between the unsteady or steady polishing force and the polishing capability of the magnetic brush is explored in an attempt to construct a model for predicting polishing forces.

Abstract: Chemical activity of micro-and nanosized powders during open air heating after electron beam (up to 360 keV of electron kinetic energy) irradiation has been studied. A differential thermal analysis disclosed that an initial oxidation temperature for iron powders has been decreased to ~ 30°C after electron beam irradiation. Thus, the thermal oxidative stability of iron powders in air was improved without any detected changes in other activity parameters.

Abstract: In this paper, the influence factors on high compressibility water atomized iron powder LAP100.29 were studied such as the processing parameters, the proportion of coarse particles, powder oxygen content and impurity. The results showed that, by increasing the purity of molten steel and improving atomization temperature, the iron content of water atomized iron powder particles reached more than 99.67 %, the oxygen content was less than 0.08 %, acid insoluble was less than 0.08 %, green density reached 7.21~7.22 g/cm³. The contents of +80 and -80～+100 mesh powder were 1.6 % and 7.5 %, respectively. The compressibility could be improved by the increase of the coarse particles and the reduction of the fine particles (for example, lowering the content of -325 mesh particles). Generally speaking, the compressibility of the water atomized iron powder can be improved fundamentally by reducing oxygen content, impurity content and the reasonable distribution of particle size.

Abstract: Samples made of iron powder with addition of 1.5 and 2% of molybdenum and 0-0.6% of boron were compacted at 600 MPa and sintered at 1200°C for 60 minutes in hydrogen atmosphere after mixing in Turbula mixer. The samples were deformed in a tensile test till rupture. The effect of molybdenum and boron on topography of fracture is discussed. It is noted that the sintering mechanism changes upon addition of boron particles into Fe-Mo alloy. The fractures of the studied samples were observed by means of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The addition of Mo influences the change of fracture to ductile type. The type of fracture is brittle with Mo and borides segregating to grain boundaries. In the alloys with low concentrations of molybdenum boron induces brittle transgranular fracture.

Abstract: In this study, the ejection stage during the densification process and the mechanical strength of green (unsintered) compact were studied for the binary powder compact of iron and micro crystalline cellulose (MCC). The mass percentage of MCC powder were varied between 0% to 60% of the total mass composition of the iron and MCC mixture. Three different compaction load of 30kN, 60 kN and 90 kN were applied during the compaction process. The tensile strength of the green compact was determined by conducting diametral compression test where the green compact was loaded until fracture. From the compaction experiment, green compact with 60% MCC and 40% iron is the least friable which leads to coherent and well compactable powder. This composition also results in the green compact with the highest tensile strength.