Thermophysical and Magnetic Properties of Magnetite – Polyethylene Composite

In this work, it is shown that the advantage of using matrix-stabilized magnetic nanoparticles to obtain polymer nanocomposites based on them is that such nanoparticles retain their dispersion and stability of size and shape in the technological modes of obtaining polymer nanocomposite materials, and thus ensured stable ferro- and superparamagnetic properties of the obtained target products. For the production of films by the method of hot pressing from blanks obtained in an injection molding machine or a mechanochemical mixture, a manual electrically heated hydraulic press was used. The magnetic properties of nanocomposite samples (about 50 mg on average) were studied using a vibration magnetometer. The character of the dependence of the magnetization on the magnitude of the magnetic field confirms the ferromagnetic character of the behavior of the obtained nanocomposites. The resulting film nanocomposites exhibit ferromagnetic properties at room temperature.

Modeling and optimization of 2-Chlorophenol degradation using ultrasound assisted Fe3O4@TiO2: Central Composite Design-Genetic Algorithm approach

In this study, the ultrasound-catalyst hybrid system was applied for degradation of 2-chlorophenol (2-CP) from aquatic environment. The produced catalyst was characterized by transmission electron microscopy, scanning electron microscopy, X-ray scattering, vibration magnetometer and nitrogen adsorption/desorption analysis, showing the successful synthesize of the core-shell structure of magnetic TiO2. A Central Composite Design (CCD) was applied in MATLAB software to investigate the effective parameters in degradation and evaluate the removal of 2-CP by M-TiO2-US system. Kinetics, intermediate products and catalyst reusability were determined under optimal conditions. The results indicated that pH of 4.413, catalyst dosage of 0.733 g/L, 2-CP concentration of 2.549 mg/L, ultrasound power of 55.605 W/L had the maximum degradation efficiency (97.776 %) and pH was assigned as the most effective parameter for the degradation of 2-CP. Superoxide and hydroxyl radicals were considered as the main cause of 2-CP degradation. Catalyst stability was investigated in 5 replicates and verified. The overall results show that the M-TiO2 and US hybrid system has promising performance in the degradation of 2-chlorophenol and has the ability to use on a larger scale.

Структура и магнитные свойства слоевых нанопроволок из 3d-металлов, полученных методом матричного синтеза

Arrays of layered nanowires (NWs) with a diameter of 100 nm consisting of alternating layers of Ni/Cu and Co/Cu were obtained by matrix synthesis based on polyethylene terephthalate track etched membranes. The process of galvanic deposition was studied and the regimes of obtaining of layered nanowires with different thicknesses of magnetic (Ni or Co) and non-magnetic (Cu) components of layers were determined. Electron microscopic investigation was performed to verify regimes of obtaining of layered nanowires and to refine the geometric properties of alternating layers. Using vibration magnetometer, the magnetization curves of the obtained arrays of layered NWs was measured at room temperature for two limiting orientations of the scanning magnetic field: parallel and perpendicular to the growth axis of the NW. It is shown that the magnetic anisotropy of the NW array is determined not only by the chemical composition, but also by the thickness and period of alternating magnetic layers in the NW. Numerical calculations of the dependence of the magnetostatic energy and the magnitude of the demagnetizing field in the synthesized layered NWs on the factor of their filling with a magnetic metal are carried out, which are qualitatively consistent with experimental observations.

Influence of Isothermal Heating on the Curie Temperature of FeCoB Bulk Amorphous Alloy

The article presents the results of research on the thermal treatment of amorphous alloys. As part of the work, an alloy with a chemical composition Fe63Co8Y8W1B20 was produced by rapid cooling. The method used to aspirate the liquid alloy into the copper mold was used. The produced material was subjected to annealing at 940K for 10 minutes. The alloy, after solidification and after heat treatment, was subjected to structure testing by means of X-ray diffraction. The soaking process led to the partial crystallization of the amorphous precursor. Using the Faraday magnetic balance, curves of the magnetic saturation polarization as a function of temperature were recorded, on the basis of their analysis, the Curie temperature of the produced materials was determined. Using the vibration magnetometer, the primary curves of magnetization and static magnetic hysteresis loops were measured. The alloy after the soaking process was characterized by higher Curie temperature and magnetically hard properties. The test results confirm the possibility of modifying the magnetic properties of high-temperature alloys through a suitably designed heat treatment.

Structural and Magnetic Properties of the Rapid Cooled Alloys: Fe60Co10Y5+xZr5-xB20 (Where: x = 0 or 2)

This article presents the results of tests on high-temperature alloys, produced on the basis of the FeCoB matrix. The nanocrystalline material was produced in a single-step process of rapid cooling of liquid alloy that was injected into a copper mould. Alloy samples were obtained in the form of 10mm x 5mm x 0.5mm tiles. Studies of the structure of the manufactured alloys were undertaken using Bruker X-ray analysis equipment (featuring a CuKa lamp). The magnetic polarization of saturation was measured, as a function of temperature, using a Faraday magnetic balance; the measurements ranged from room temperature up to 850K. Through numerical analysis of the curves, the Curie temperature of the investigated alloys was determined. Using a vibration magnetometer, static magnetic hysteresis loops were measured. The magnetization of saturation of the tested alloys was greater than 1 T, while the coercive field values were 400 and 16600 A/m. The stiffness parameter of the spin wave Dspf was determined.

Magnetic Properties of FeCoWYB-based Ferromagnetic Alloys with a Small Addition of Pt

The paper presents the results of research on the effect of Pt addition in the amount of 2 to 3% at. in to bulk Fe61Co10B20Y8-xW1Ptx alloy on its structure and magnetic properties. Alloys in the form of tiles were made by pressing a liquid alloy into a copper liquid-cooled mold. Structural examinations were carried out using X-ray diffraction (XRD). The magnetic properties were examined using a vibration magnetometer (VSM). Based on structural investigations, the occurrence of crystalline phases, i.e.: a-Fe, Fe2B, FePt, Fe3Pt, FePt3, was found. The results of VSM tests showed that both saturation magnetization (m0Ms) and coercive field (Hc) significantly increased. The study showed that even a small change in the Pt content in the alloy affects its structure and thus significantly affects the magnetic properties.

Influence of the Process for Obtaining Massive Amorphous Materials on the Defects of the Structure in the Alloy Fe61+xCo10-xY8W1B20 , where x = 0 or 1

As part of the work, a rapid cooled alloy was produced with the chemical composition Fe61+xCo10-xY8W1B20, where: x = 0 or 1 using two methods, suction in and injecting the molten alloy into the copper mold. The material was obtained in the form of 10 mm x 5 mm x 0.5 mm plates. Studies on the structure of the obtained alloys were carried out using X-ray diffraction. Obtained X-ray diffraction images are typical for amorphous materials. Using the vibration magnetometer, static magnetic hysteresis loops and primary magnetization curves were measured. The produced samples are characterized by a saturation value above 1T and a coercive field value below 200 A/m. Based on the theory of H. Kronm�ller, numerical analysis of the curves of the original magnetization was carried out. It has been found that the process of magnetizing the produced materials has defects of the amorphous structure in the form of pseudo-location dipoles and free volumes. In addition, the spin wave stiffness parameter was determined.

Structure and Magnetic Properties of Composite Toroids Powder Casted

The paper presents the results of research for magnetic composites made of metallic filler from alloy Fe65Co10Ni3W2B20 and epoxy resin EPIDIAN 100. The composites studied contained less than 10% of the resin, making them dimagnetoelectrics. The structure of alloys and composites was investigated using X-ray diffraction and scanning electron microscopy and their magnetic properties using a vibration magnetometer. It has been shown that the structure and properties of the composites depend on the chemical composition of the metallic filler. And good link between components, with the proper placement of the filler in the matrix, has an impact on the quality of the composite.

Study on Preparation of Oil-Based Fe3O4 Nano Magnetic Fluid

Adopting chemical coprecipitation and mechanical dispersion to prepare oil based magnetic fluid is a good way to increase the stability of magnetic fluid. This paper uses orthogonal design to analyze the influences from different factors, and The size of nano-particles and saturation magnetization were characterized by TEM and WSM vibration magnetometer. The results show that the NaOH solution adding speed of 0.4 ml/s and reaction temperature of 50 ~55 , sodium oleate solution adding speed of 0.3ml/s and heating temperature of 65 , heat-maintaining time of 20min are proper reaction conditions.