J. Appl. Cryst.の発刊に際して

Nuclear Instruments and Methods in Physics Research. Section B; Microstructural Characterization of Semi-Interpenetrating Polymer Networks by Positron Lifetime Spectroscopy

Metrological characterization of X-ray diffraction methods at different acquisition geometries for determination of crystallite size in nano-scale materials

The aim of this study was to evaluate the magnetic properties of hybrid epoxy-based composite materials with magnetic barium ferrite (BaM) and conductive carbon (multi-walled carbon nanotubes and graphite nanoplatelets) fillers. This study was performed in order to fabricate composites with uniform and aligned magnetic components of the filler. The magnetization field dependences of the composites and BaM powder were determined and analyzed using a vibrating magnetometer. Of additional concern was the filler distribution characterization by optical investigation. Coercivity of BaM/epoxy composites increases more than in 4 times in comparison with BaM powder. Composites with aligned filler reveal an anisotropy of the magnetization relative to the alignment axis. However, BaM particles retain their uniform distribution in aligned fibers, which is confirmed by a magnetic remanence-to-saturation magnetization (M(0)/M
 max) ratio of 0.5.

Magnetic anisotropy of the graphite nanoplatelet–epoxy and MWCNT–epoxy composites with aligned barium ferrite filler

This paper discusses the investigation of pure MgO, ZnO nanoparticles (NPs) and ZnO/MgO nanocomposites (NCs) via plant based green assisted simple, fast, economical and environmental friendly method with the help of Ricinus communis L. plant seedless fruit extract (SFE). The green route synthesized NPs and NCs calcinated at the temperature of 450 °C were used for further optical studies with ultraviolet–visible spectroscopy (UV–vis), structural studies by X-ray diffraction (XRD), functional analysis by Fourier-transform infrared spectroscopy (FTIR), microscopic determination by scanning electron microscope and transmission electron microscope (SEM, TEM), elemental composition analyzed by using Energy-dispersive X-ray spectroscopy (EDX). Successfully synthesized and characterized NPs and NCs were, further, used for the antibacterial studies towards Escherichia coli (E.coli), Klebsiella bacteria(s) and photocatalytic activity towards methylene blue (MB). In comparison to the pure NPs and NCs, the ZnO/MgO-NCs (1:1) exhibited an enhanced antibacterial activity and resulted in 1.5–2.8 times and 1.27–3.5 times larger radius for zone of inhibition in case of E.coli and Klebsiella respectively, where as the value for photocatalytic apparent rate constant was found to be 1.49–5.25 times more.

Phytoextract mediated ZnO/MgO nanocomposites for photocatalytic and antibacterial activities

Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment. Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM). Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950 °C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force (HC) for mixture of powders annealed at 950 °C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. The arithmetic mean of diameter of Fe2O3 and BaCO3 mixture powders after 30 hours of milling is about 6.0 μm. Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable components to produce sintered and elastic magnets with polymer matrix. Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials.

Barium ferrite powders prepared by milling and annealing

Dispersion analysis of NiAl-TiC-Al2O3 composite powder ground in a high-energy attritorial mill

Influence of alloying additions and annealing time on magnetic properties in amorphous alloys based on iron

Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The morphology of Fe2O3 and BaCO3 powders after milling was analyzed using the scanning electron microscopy (SEM) method. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM). Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases and leads to increase the content of Fe2O3 phase and decrease of BaCO3 content. Milling process causes enriching of surface layer of powder particles by Fe2O3. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950°C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force for the mixture of powders annealed at 950°C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. From morphology images and distribution of powder particle size it can be concluded, that the size of tested powder particles increases with increasing time of milling process. The increase of milling time up to 20 hours leads to joining of smaller particles in bigger ones; agglomerates are formed. Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable component to produce sintered and elastic magnets with polymer matrix. Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials.

L. Pająk

Papers

Barium ferrite powders prepared by milling and annealing

Dispersion analysis of NiAl-TiC-Al2O3 composite powder ground in a high-energy attritorial mill

Influence of alloying additions and annealing time on magnetic properties in amorphous alloys based on iron

Structure and properties of barium ferrite powders prepared by milling and annealing

Microstructure of Ni(Cr)-TiC-Cr3C2-Cr7C3 composite powder