Iron Alloy Particles Research Articles

An Experimental Study on the Properties of Recycled High-Density Polyethylene

Abstract Recycling of plastic materials has become more environmentally important than recycling of other materials. The most important problem during recycling is the presence of oil, dirt, dust and metal particles that are mixed with plastic materials. These mixtures can change their its mechanical and physical properties and it is quite costly to remove them completely. Removing iron alloy particles from plastic is possible by using the magnetic method. However, removing non-metallic materials requires extra processing. In this study, the use of recycled High-Density Polyethylene (rHDPE) without an expensive cleaning processes has been investigated. Different amounts of aluminium oxide (Al2O3) were added to High Density Polyethylene (HDPE) to simulate the effect of non-metallic material involved. The effect of these contamination rates on the mechanical and physical properties of HDPE was examined in detail. For this purpose, recyclable materials were produced by mixing rHDPE with 1%, to 7% Al2O3 . The results show that up to 7% of the mixture has acceptable effects on the properties of HDPE. When the results of the experiments are examined, it is observed that there is a 3.74% change in the elastic modulus of the material. This means, that up to 7% non-metal contaminated rHDPE material can be used without any costly recycling process.

Rapid removal of chloroform, carbon tetrachloride and trichloroethylene in water by aluminum–iron alloy particles

ABSTRACTWater contamination with chlorinated hydrocarbons such as chloroform (CHCl3), carbon tetrachloride (CCl4) and trichloroethylene (TCE) is one of the major public health concerns. In this study, we explored the use of aluminum–iron alloys particles in millimeter scale for rapid removal of CHCl3, CCl4 and TCE from water. Three types of Al–Fe alloy particles containing 10, 20 and 58 wt% of Fe (termed as Al–Fe10, Al–Fe20 and Al–Fe58) were prepared and characterized by electrochemical polarization, X-ray diffraction and energy dispersive spectrometer. For concentrations of 30–180 μg/L CHCl3, CCl4 and TCE, a removal efficiency of 45–64% was achieved in a hydraulic contact time of less than 3 min through a column packed with 0.8–2 mm diameter of Al–Fe alloy particles. The concentration of Al and Fe ions released into water was less than 0.15 and 0.05 mg/L, respectively. Alloying Al with Fe enhances reactivity towards chlorinated hydrocarbons' degradation and the enhancement is likely the consequence of galvanic effects between different phases (Al, Fe and intermetallic Al–Fe compounds such as Al13Fe4, Fe3Al and FeAl2) and catalytic role of these intermetallic Al–Fe compounds. The results demonstrate that the use of Al–Fe alloy particles offers a viable and green option for chlorinated hydrocarbons' removal in water treatment.

Novel magnetoelectric composites of cobalt iron alloy and barium titanate

AbstractMagnetoelectric barium titanate ceramics with embedded cobalt iron alloy particles (Co1/3Fe2/3)x–(BaTiO3)(1−x), with x=0.2, 0.4, and 0.6, were prepared by a polyol‐mediated synthesis with subsequent sintering in a reducing forming gas atmosphere. The samples were characterized by XRD and SEM/EDX measurements. The sizes of the Co1/3Fe2/3 grains increase with x. Impedance spectroscopy showed a behavior similar to pure BaTiO3, in particular the occurrence of the ferroelectric‐paraelectric phase transition, and high permittivities for the sample with x=0.6, that is, near the percolation threshold. The samples exhibit soft ferromagnetic properties with large saturation magnetizations of 2.5 μB/atom and narrow hystereses. Detailed magnetoelectric investigations revealed a unique DC‐field dependence of αME for all three compositions. Most remarkably, the sample with x=0.4 possesses a broad ME hysteresis and an inversion of the sign of αME at 5 kOe.

Nitrate reduction in water by aluminum–iron alloy particles catalyzed by copper

Nitrate contamination is increasingly becoming a global health and environmental issue, because nitrate concentration in ground and surface waters has exceeded the safe limit in many places of the world. Removal of such low levels of nitrate from water by conventional processes in an efficient and cost-effective manner poses a significant challenge in water treatment industry. Chemical reduction using zero-valent iron and aluminum particles for nitrate removal from water has been extensively investigated. In this study, aluminum–iron alloy particles (containing 10% iron) were investigated for removal of nitrate from water and compared with zero-valent aluminum, iron and mixtures of aluminum and iron particles. The aluminum–iron alloy and metallic aluminum particles were inactive for nitrate reduction due to the presence of ubiquitous aluminum oxide layer on surface of the particles. Nitrate reduction was significantly promoted by copper chloride and the alloy particles showed the fastest rate and largest efficiency of the reduction. The significant promotion of the reduction was likely due to the catalytic effect of copper and an intermetallic alloy compound Al13Fe4. The catalytic mechanism of nitrate reduction by the alloy material was analyzed and the reduction pathway was identified as nitrite and ammonium to be intermediate and end product, respectively.

Moderate velocity oblique impact sliding: Production of shocked meteorite textures and palaeomagnetically important metallic spherules in planetary regoliths

AbstractWe detail the production of metallic spherules in laboratory oblique shock impact experiments, and their applicability (1) to textures in a partly shock‐melted chondritic meteorite and (2) to the occurrence of palaeomagnetically important fine iron or iron alloy particles in the lunar regolith. Samples recovered from 29–44 GPa, 800 ns, experiments revealed melting and textures reminiscent of metallic spherules in the Yanzhuang H‐chondrite, including “dumbbell” forms and other more complex morphologies. Our experiments demonstrate that metallic spherules can be produced via oblique impact sliding at lower velocities (1.85 km s−1) than are generally assumed in previous work associated with bulk‐shock melting, and that oblique impact sliding is a viable mechanism for producing spherules in shock‐induced veins in moderately shocked meteorites. Significantly, our experiments also produced fine metallic (iron alloy) spherules within the theoretical narrow size range (a few tens of nanometers for slightly ellipsoidal particles) for stable single‐domain (SSD) particles, which are the most important palaeomagnetically, since they can record lunar and planetary magnetic fields over geological time periods. The experiments also produced spherules consistent with superparamagnetic (SP) and multidomain (MD) particle sizes. The fine SSD and SP particles on the lunar surface are currently thought to have been formed predominantly by space weathering processes. Our experiments suggest that oblique shock impact sliding may be a further means of producing the SSD and SP iron or iron alloy particles observed in the lunar regolith, and which are likely to occur in the regoliths of Mercury and other planetary bodies.

FeNbVBALLOY PARTICLES SUSPENDED IN LIQUID GALLIUM: INVESTIGATING THE MAGNETIC PROPERTIES OF THE MR SUSPENSION

A MR suspension was prepared by dispersing silica-coated iron alloy particles into a liquid gallium. In other words, the iron alloy particles of 30 to 50 nm in diameter were first prepared and then coated with silica. Next, the particles were then suspended in a liquid Ga (assay: 99.9999%). In addition, the magnetic properties of the synthesized particles and suspension under the influence of the magnetic field were investigated. One of the main findings of this study is that the prepared powder showed a temperature sensitive of magnetization within the testing temperature range of 293–353 K. The saturation magnetization of silica-coated FeNbVB particles was about 0.55 T, whereas the saturation magnetization (297 K) of the synthesized MR suspension was 0.019 T.

都市公共用水域に対するノンポイント汚染源としての道路脇粉塵（＜６３μｍ画分）の化学的特徴―名古屋市の事例―

The chemical composition of fine fractions (<63μm) of street dust in Nagoya City, central Japan, is examined to obtain information on the nonpoint pollution load of river and sewer systems in urban areas. The results show that the fine fractions of street dust have more C, Fe, Mn, Ca, Mg, P, Cr, Zn, Sb, As, Hf, and Au than hypothetical background level. Additionally, Ti and Co are also derived significantly from anthropogenic sources. Among these “enriched elements”, C, Ca, P, Zn and Ti are likely derived from tire and asphalt dusts, whereas Fe, Mn, Co and possibly Cr appear to be incorporated into street dust as iron alloy particles. These metallic iron particles are also considered to be derived from parts of vehicles such as their bodies and brake disks.

Calculations of giant magnetoelectric effects in ferroic composites of rare-earth–iron alloys and ferroelectric polymers

Coupled magnetic-mechanical-electric effects involving linearly and nonlinearly coupling interactions in ferroic composites are investigated using a Green's function technique. We use the theory to suggest a possible giant magnetoelectric effect in a ferroelectric poly(vinylidene fluoride-trifluorethylene) copolymer filled by giant magnetostrictive rare-earth--iron alloy particles, which is markedly larger than that in the best known magnetoelectric materials. The flexible composite is expected to exhibit large magnetostriction. Our results show how to design such flexible polymer-matrix magnetoelectric composites with better performance and may stimulate further interest in the areas of coupled multifield effects and magnetoelectric materials for practical applications.

MAGNETORHEOLOGICAL MATERIALS BASED ON IRON ALLOY PARTICLES

A magnetorheological material containing iron alloy particles demonstrates magnetorheological strength dependent upon the elements of the alloy and relative concentration of the alloy elements. Selected iron/cobalt alloys demonstrate improved yield strength over traditional carbonyl iron based MR materials when the iron-cobalt alloy has an iron-cobalt ratio ranging from about 30:70 to 95:5. The iron-nickel alloys which have an iron-nickel ratio ranging from about 90:10 to 99:1 maintains superior strength over iron-nickel alloys outside that range.

Interaction of a vinyl acetate—vinyl chloride based wetting binder with metal particles for magnetic recording

The interaction of two commercially available iron alloy particles with a wetting binder based on a vinyl chloride and vinyl acetate copolymer has been investigated. The interaction was studied using the techniques of flow microcalorimetry, X-ray photoelectron spectroscopy (XPS) and microelectrophoresis. The results obtained indicate that whereas both particles interact strongly with the wetting binder, particles of low nickel content are characterized by very high heats of interaction (about 37–47 kcal mol −1). The adsorption on both particles appears to obey the Freundlich equation. Binder adsorption on particles results in the development of rather large zeta potentials in tetrahydrofuran solutions. XPS experiments are unable to provide any conclusive evidence for the interaction mechanism.

Gyroremanent magnetization in magnetic tape and in iron and iron-alloy particles

Rotational remanent magnetization (RRM) and rotational anhysteretic remanent magnetization (ARM) have been produced in iron and iron alloys by rotating the samples in a slowly decreasing alternating field (80 mT initial peak). Coarse multidomain iron grains, and excarbonyl iron consisting of 1-9- mu m spheres, exhibited negligible RRM but a large ARM. Samples of metallic tape and Alnico permanent magnet alloys (Alcomax and Hycomax III), all of which consist of fine elongated particles, acquired a large RRM, which for a rotation frequency near twice the AF frequency (50 Hz) was comparable to or greater than an ARM produced under identical conditions (in a steady field of 44 mu T). The results are consistent with the gyromagnetic hypothesis of RRM acquisition in single-domain grains and also with previous results for magnetite.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>