J. Szala

Ferroelectric properties of ultrasonochemically prepared SbSI ethanogel.

This article presents for the first time the electrical properties of sonochemically synthesised, high-surface-area SbSI ethanogel made up of large quantity nanowires with lateral dimensions of about 10-50 nm and lengths reaching up to several micrometers. The composition, morphology, dimensions, microstructures, and optical energy gap of the new form of SbSI were characterized. This material is a semiconducting ferroelectric as in the case of bulk SbSI crystals. The maximum of dielectric constant epsilon=1.6x10(4) is observed at Tc=292(1) K. The activation energies in temperature dependences of electric conductivity of SbSI ethanogel are different for ferroelectric and paraelectric phases during heating and cooling of the sample.

Characterization of reinforcement distribution in Al/(Al2O3)p composites obtained from composite powder

A composite powder Al–(Al2O3)p obtained in a rotary-vibration mill was used as a semifinished component to manufacture particle-reinforced metal matrix composites (PRMMCs) using cast and powder metallurgy technologies. For a quantitative description of the inhomogeneity of Al2O3 particle distributions in the aluminum matrix the following methods were applied: nearest neighbor distance, radial distribution function, influence zone morphology, systematic scanning and variance analysis. All the methods showed a significantly less inhomogeneous distribution of reinforced particles in the composite manufactured with the powder metallurgy method. It was also shown that systematic scanning and variance analysis method enables precise descriptions of particle clustering as well as composite microstructure anisotropy.

Sonochemical preparation of SbS1−xSexI nanowires

A sonochemical method for direct preparation of nanowires of SbS(1-x)Se(x)I solid solution has been established. The SbS(1-x)Se(x)I gel was synthesized using elemental Sb, S, Se and I in the presence of ethanol under ultrasonic irradiation (35kHz, 2W/cm(2)) at 50 degrees C for 2h. The product was characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray analysis, selected area electron diffraction, and optical diffuse reflection spectroscopy. The SEM and HRTEM investigations exhibit that the as-prepared samples are made up of large quantity nanowires with lateral dimensions of about 10-50nm and lengths reaching up to several micrometers and single-crystalline in nature. The increase of molar composition of Se affects linear decrease of the indirect forbidden optical energy gap as well as the distance between (121) planes of the SbS(1-x)Se(x)I nanowires.

Sonochemical growth of antimony sulfoiodide in multiwalled carbon nanotube.

This paper presents for the first time the nanocrystalline, semiconducting ferroelectrics antimony sulfoiodide (SbSI) grown in multiwalled carbon nanotubes (CNTs). It was prepared sonochemically using elemental Sb, S and I in the presence of methanol under ultrasonic irradiation (35kHz, 2.6W/cm(2)) at 323K for 3h. The CNTs filled with SbSI were characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction, and optical diffuse reflection spectroscopy. These investigations exhibit that the SbSI filling the CNTs is single crystalline in nature and in the form of nanowires. It has indirect forbidden energy band gap E(gIf)=1.871(1)eV.

Sonochemical preparation of SbSeI gel

A novel sonochemical method for direct preparation of nanocrystalline antimony selenoiodide (SbSeI) has been established. The SbSeI gel was synthesized using elemental Sb, Se, and I in the presence of ethanol under ultrasonic irradiation (35 kHz, 2W/cm(2)) at 50 degrees C for 2h. The product was characterized by using techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and optical diffuse reflection spectroscopy (DRS). The SEM and HRTEM investigations exhibit that the as-prepared samples are made up of large quantity nanowires with lateral dimensions of about 20-50 nm and lengths reaching up to several micrometers and single crystalline in nature.

Influence of the solvent on ultrasonically produced SbSI nanowires

The influence of the substitution of methanol in place of ethanol during the ultrasonic production of antimony sulfoiodide (SbSI) nanowires is presented. The new technology is faster and more efficient at temperatures greater than 314 K. The products were characterized by using techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), optical diffuse reflection spectroscopy (DRS) and IR spectroscopy. The coexistence of Pna2(1) (ferroelectric) and Pnam (paraelectric) phases at 298 K was observed in the SbSI nanowires produced in methanol. The methanol decomposes during the sonication or due to the adsorption process on SbSI nanowires.

Sonochemical preparation of antimony subiodide

The substantiated isolation of the antimony subiodide (Sb(3)I) is presented for the first time. It has been prepared using elemental Sb and I in ethanol under ultrasonic irradiation at 323 K. Its composition was characterized using X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDAX). The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) investigations exhibit that the samples are made up of large quantity of nanoparticles with diameters smaller than 20 nm and single crystalline in nature. The interplanar spacings in Sb(3)I that have been determined using powder X-ray diffraction (XRD), selected area electron diffraction (SAED) and HRTEM are very similar. Surprisingly, the registered XRD patterns are identical to the one reported earlier for Sb(4)O(5)I(2).

Influence of Al–Al2O3 composite powder on the matrix microstructure in composite casts

Abstract The structural characterization is presented of composite casts with an AlMg4 alloy matrix, with the composite powder (Al–Al2O3)cp reinforcement obtained in a rotary-vibration mill. On the cross-sections of ingots, metallographic specimens have been made and, by means of quantitative metallographic methods, the grain size distributions have been determined. Statistical tests of the results obtained from the grain plane section area measurements have been performed. An influence has been found of the (Al–Al2O3)cp composite powder on the matrix grain size distribution, depending on the distribution of the composite powder particles in the ingot, whereas no influence of (Al–Al2O3)cp on the mean grain size of the AlMg4 alloy has been found.

Comparison of the Investigations of Photonic Crystals Using SEM and Optical Technics

All over the world the investigations of nanophotonic structures called photonic crystals (PCs) are performed. These crystals have potential applications in optoelectronics, e.g. optical filters, antireflective surface coatings, lossless frequency selective mirrors. In Institute of Physics at Silesian Technical University the opal photonic crystals consisting of monodisperse spherical particles, that have diameters of several hundred nanometers, are produced using colloidal self-assembly technics. The main aim of this work is the comparison between pieces of information on morphology of photonic crystals that can be obtained from electron microscopy and from the angular characteristics of optical transmittance and reflectance. The morphology of the samples is characterized by scanning electron microscopy (SEM). Nanosphere diameters are established from statistical analysis of SEM images. The optical properties, which are determined by the photonic band structure, are studied by means of light transmission and reflection measurements. There is a relationship between the wavelength position of transmittance minimum or reflectance maximum and the diameter of the nanospheres. The size of nanospheres obtained from optical measurement results were compared with data obtained from SEM images.

Economical non-ledeburitic tool alloys—alloying philosophy, structure and properties

Abstract Economical non-ledeburitic tool alloys are materials of significantly lower carbide particles segregation than in conventional HSSs. Owing to worked out carbon and carbide formers balance, classical eutectic carbides were replaced by primary, hard MC type carbide particles of uniform arrangement. Numerous variants of wrought and cast alloys were produced; tools made of these materials exhibited high service properties.