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  1. 87 Acta Physica Polonica A

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  1. 5 Godlewski M.

  2. 4 Phillips M.

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1
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The Preparation of Core-Shell Al_2O_3/Cu Composite Powders by Electroless Plating in the Alkaline Solution

100%
Uysal M., Karslioğlu R., Alp A., Akbulut H.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
238-240
EN
In this study, Cu-coated Al_2O_3 composite powders were synthesized by using electroless plating method. The influence of the plating bath composition and ceramic powder concentration on the Cu plating was characterized by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction techniques. The results showed that the electroless bath composition plays an important role for the structure of nano core-shell Al_2O_3/Cu composite powders. The content of copper in the composite powders could be effectively controlled by adjusting the content of copper sulfate and formaldehyde in the plating solution. Furthermore, the pretreatment of the Al_2O_3 powders is also a key factor to form a uniform shell copper layer coating on Al_2O_3 particles.
2
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Structure and Properties of Soft-Magnetic Amorphous Bilayer Ribbons

63%
Švec P., Mat'ko I., Marcin J., Kováč J., Vlasák G., Janičkovič D., Škorvánek I., Švec P.
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issue 5
832-834
EN
Rapidly quenched bilayers consisting of Fe-Si-B and Co-Si-B layers have been prepared by planar flow casting from a single crucible with two nozzles. Temperature dependences of electrical resistivity, dilatation and magnetization have been investigated in the amorphous state and during crystallization of both layers. Preliminary studies of the structure of the layers and of the interlayer have been performed by X-ray diffraction, cross-sectional electron microscopy and microanalysis. From the results it seems evident that the process of connection of the two layers during preparation takes place by solidification with only a small extent of mutual interdiffusion of component atoms localized to a narrow well-defined interface, leading to mechanically solid connection between the two layers. The effect of combined presence of two different soft magnetic alloys on the overall magnetic properties is discussed with respect to potential applications of such materials.
3
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Effect of Substrate Temperature on the Structural and Optical Properties of Nanocrystalline Cadmium Selenide Thin Films Prepared by Electron Beam Evaporation Technique

63%
Suthan Kissinger N., Suthagar J., Saravana Kumar B., Balasubramaniam T., Perumal K.
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issue 4
623-628
EN
Cadmium selenide (CdSe) thin films on glass substrates were prepared by physical vapour deposition under vacuum using the electron beam evaporated technique for different substrate temperatures: room temperature, 100, 200, 300°C, respectively. X-ray diffraction analysis indicates that the films are polycrystalline, having hexagonal (wurtzite) structure irrespective of their substrate temperature. All the films show most preferred orientation along (0 0 2) plane parallel to the substrates. The microstructural parameters such as particle size, stress, strain and dislocation density were calculated. The grain size of deposited CdSe films is small and is within the range of 18 to 42 nm. The optical absorption spectra of electrom beam deposited CdSe films were studied in the wavelength region of 250-2500 nm. The energy gap (E_{g}) values (allowed direct transitions), calculated from the absorption spectra, ranged between 1.77 and 1.92 eV. The surface morphological quality of electron beam evaporated CdSe films were analyzed by scanning electron microscopy and atomic force microscopy.
4
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Martensite Reorientation after Thermal Cycling in NiTiCu Shape Memory Alloys Studied by EBSD Technique

63%
Rak J., Goryczka T., Ochin P.
Acta Physica Polonica A
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2016
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vol. 130
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issue 4
1075-1078
EN
The Ni₂₅Ti₅₀Cu₂₅ shape memory alloy exhibits one-step martensitic transformation. Transformation occurs between the B2 parent phase and the B19 orthorhombic martensite. The course of the martensitic transformation was in situ studied in the alloy with use of electron backscatter diffraction. During heating, reverse martensitic transformation occurs from the B19 orthorhombic martensite to the B2 parent phase. On cooling, from the parent phase the B19 martensite is formed. Obtained results proved that the B19 martensitic plates forms the variants indexed as 1, 3, and 5. Thermal cycling does not change the crystallographic correlation between the parent phase and the martensite. However, after cycling, different rearrangement of the martensitic plates can be received. In consequence, characteristic temperatures of the martensitic transformation are shifted.
5
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Leaching Effect on Multiple Surfaces of a Single Grain Decagonal Al-Ni-Co Quasicrystal

63%
Lowe M., Gille P., McGrath R., Sharma H.
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vol. 126
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issue 2
520-523
EN
We have studied the effect of leaching treatments on the surface microstructure and chemical composition on the two different twofold surfaces, (10000) and (101̅00), and the tenfold surface (00001) of a decagonal (d-) Al-Ni-Co quasicrystal. A sample exposing the three surfaces was leached with NaOH solution and then studied using atomic force microscopy and scanning electron microscopy combined with energy dispersive X-ray analysis. The leaching treatment preferentially removes the Al present in the crystal surface leaving a mixture of transition metal and their associated oxides. The high symmetry, tenfold axis was found to be less resistant to leaching than either of the twofold axes, providing further information regarding the effect of crystallographic direction on leaching kinetic.
6
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New Functional Materials Based on Nano- and Micro-Objects with Developed Surface

63%
Dorogov M., Dovzhenko O., Gryzunova N., Vikarchuk A., Romanov A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 4
503-505
EN
The paper describes the materials with a developed surface fabricated on the basis of electrodeposited copper icosahedral small particles and coatings made of such particles. Increasing the specific surface area of the electrolytic metal is achieved by special heat and/or chemical treatments. Changes in the structure and morphology of icosahedral small particles are analyzed with scanning electron microscopy and X-ray diffraction. The specific surface area of the material is determined with low-temperature gas adsorption technique. Annealing of icosahedral small particles and coatings leads to the formation of the porous structure and a "forest" of whiskers on their surface. Chemical etching of icosahedral small particles corrodes the inside material and provides the formation of hollow particles. Possible applications for obtained materials with a developed surface are offered.
7
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Composition and Microstructure of Surface Layers Produced by Ion Beam Assisted Deposition of Metals from a Pulsed Arc-Discharge Plasma onto Aluminum Substrates

63%
Poplavsky V., Komarov F., Luhin V., Pil'ko V., Partyka J.
Acta Physica Polonica A
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2015
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vol. 128
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issue 5
946-948
EN
Ion beam assisted deposition of alloying metals (Zn, Cd, Zr, Cr) onto pure aluminum and aluminum alloy substrates from the plasma of a pulsed arc discharge for the purpose of materials corrosion stability was carried out. The Rutherford backscattering spectrometry, electron backscatter diffraction, scanning electron microscopy, and electron probe microanalysis methods were applied to investigate composition and microstructure of the prepared layers. It was found that the obtained layers are characterized by amorphous atomic structure and contain the atoms of deposited metal, substrate material components, as well as impurities of oxygen and carbon; their thickness was measured to be ≈ 30-100 nm.
8
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Effect of Two-Step Oxidation on Performance of Micro-Arc Oxidation on 6063 Aluminum Alloy

63%
Ayday A.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
96-98
EN
This paper investigates the effect of different electrolytes containing silicate and phosphate by two-step oxidation using the micro-arc oxidation technique. The growth effect, surface roughness, and element distributions of the micro-arc oxidation coatings were characterized. The composition of coating was characterized using X-ray diffraction and energy dispersive spectrum, and the morphology was examined using scanning electron microscope. The surface characterizations results show that the coating growth forms are different in Si and P electrolytes while the coated samples were almost composed of γ-Al₂O₃.
9
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X-ray Diffraction and EBSD Study of Al-Ti-Co-Ni-Fe High-Entropy Alloy

51%
Górecki K., Bała P., Cios G., Stępień M., Kozieł T., Wieczerzak K., Tokarski T.
Acta Physica Polonica A
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2016
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vol. 130
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issue 4
991-992
EN
Al₁₅Ti₂₀Co₂₀Ni₂₅Fe₂₀ alloy, synthesized in an arc furnace, was characterized by microscopic investigations, X-ray diffraction and electron backscatter diffraction techniques. Theoretical assumptions indicate a dual-phase crystal structure fcc+bcc. It was shown that dendrites and eutectic are bcc phase, and the interdendritic region is fcc phase.
10
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Content available

Cathodoluminescence Profiling of InGaN-Based Quantum Well Structures and Laser Diodes - In-Plane Instabilities of Light Emission

51%
Godlewski M., Ivanov V., Goldys E., Phillips M., Böttcher T., Figge S., Hommel D., Czernecki R., Prystawko P., Leszczynski M., Perlin P., Grzegory I., Porowski S.
Acta Physica Polonica A
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2003
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vol. 103
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issue 6
689-694
EN
Instabilities of light emission and also of stimulated emission in series of GaN epilayers and InGaN quantum well structures, including laser diode structures, are studied. A stimulated emission is observed under electron beam pumping. This enabled us to study light emission properties from laser structures and their relation to microstructure details. We demonstrate large in-plane fluctuations of light emission and that these fluctuations are also present for excitation densities larger than the threshold densities for the stimulated emission.
11
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Fabrication and Optical Characterization of CdSe Thin Films Grown by Chemical Bath Deposition

51%
Kariper İ., Bağlayan Ö., Göde F.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-219-B-221
EN
Cadmium selenide thin films with different pH values (pH = 10, 11, 12 and 13) are produced on glass substrates at 50°C for 3 h by chemical bath deposition technique. The structural, morphological and optical properties of the films are characterized by X-ray diffraction, scanning electron microscopy and optical absorption spectroscopy, respectively. The obtained films have hexagonal structure. The optical transparency of the films varies between 85% and 98% at wavelength of λ = 550 nm. The scanning electron microscopy studies show that the film deposited at pH = 10 exhibits the formation of nanorods in the width range from 1.8 μm to 10.9 μm and length range from 20.0 μm to 85.5 μm. The optical properties of the films are determined by measuring transmittance and absorbance characteristics which are used to find the optical band gap energy, refractive index, extinction coefficient and real dielectric constant. The band gap width of the films increases from 1.70 eV to 2.30 eV with increasing pH values. The refractive index of the film at pH = 10 is found as 1.54.
12
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Dependence of Tin Whisker Growth on Copper and Oxygen Content on the Surface of Tin-Rich Lead Free Alloys

51%
Skwarek A., Witek K., Pluska M., Czerwinski A.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
430-431
EN
The introduction of lead-free technology into electronics has intensified concern over tin whiskers phenomenon. Tin whiskers are crystals growing from the alloy surface as the result of compressive stress relaxation. This paper presents the dependence of tin whisker growth on copper and oxygen surface content. The observations and measurements were done using scanning electron microscopy with energy-dispersive X-ray spectroscopy. The results show that whisker growth is strongly related to increased copper and oxygen surface content in whisker neighborhood.
13
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Effect of Secondary Electroluminescence on Cathodoluminescence and Other Luminescence Measurements

51%
Pluska M., Czerwinski A., Szerling A., Ratajczak J., Kątcki J.
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vol. 125
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issue 4
1027-1032
EN
Cathodoluminescence and photoluminescence measurements are commonly accepted as revealing local properties of a specimen region excited by a beam of electrons or photons. However, in the presence of a strong electric field (e.g. a junction) an electron (or light/laser) beam-induced current is generated, which spreads over the structure. A secondary non-local electroluminescence, generated by this current and detected together with the expected luminescence signal, may strongly distort measurement results. This was confirmed by cathodoluminescence measurements on test structures prepared by focused ion beam on AlGaAs/GaAs/InGaAs laser heterostructures. Methods for minimizing the distortion of measured luminescence signals are presented.
14
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Intermolecular Magnetic Spin-Spin Interaction in Asphaltene Suspensions at 1.53 mT

51%
Ovalioglu H., Kirimli H., Akay C.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
806-809
EN
In this study, Overhauser effect (OE) type of dynamic nuclear polarization (DNP) experiments were performed to study suspensions of MC800 asphaltene in bromopentafluorobenzene, chloropentafluorobenzene and hexafluorobenzene aromatic solvents. The experiments were performed at a low field of 1.53 mT in a double-resonance nuclear magnetic resonance (NMR) spectrometer. In this technique the nuclei of diffusing solvent molecules and the unpaired electron existing on the asphaltene micelles interact magnetically. The DNP parameters were determined. Additionally, the interactions between ¹⁹F nuclei of the solvent and the electrons delocalized on the asphaltene are interpreted. The highest enhancement factor value (5.90) was obtained for the hexafluorobenzene solvent medium, because between these, hexafluorobenzene has the highest fluorine atom number. The solvent molecules attach to the colloidal asphaltene particles for a very short time forming complexes and making scalar interaction. Morphologies of asphaltene surfaces depending on the solvent effects were observed by using scanning electron microscopy (SEM).
15
Content available remote

Composition of Surface Layers Prepared by Ion Beam Assisted Deposition of Catalytic Metals from Pulsed Arc-Discharge Plasma onto Carbon Paper Substrates

51%
Poplavsky V., Luhin V., Koltunowicz T.
Acta Physica Polonica A
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2017
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vol. 132
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issue 2
295-298
EN
The layers were prepared by ion beam assisted deposition of iridium and platinum onto AVCarb® Carbon Fiber Paper P50 electrocatalyst supports for the production of diffusion layers of the membrane-electrode assemblies of low temperature fuel cells with polymer electrolyte membrane. Formation of the layers in the ion beam assisted deposition mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by the accelerated (U=10 kV) ions of the same metal, was performed. In this process neutral fraction of metal vapour and ionized plasma of vacuum pulsed electric arc discharge were used. The investigations of morphology and composition of layers were carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, wave dispersive X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. It was established that the obtained catalytic layers contain atoms of the deposited metals and substrate material as well as impurity oxygen atoms. The surfaces contain also metal inclusions of several micrometer size which arise from the precipitation of deposited metal droplets from the arc discharge of an ion source. The content of iridium and platinum atoms in the layers is ≈2×10¹⁶ cm¯²; the concentration of the deposited metals equals about several atomic percent.
16
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Solution Growth and Investigation of the Single Crystals from the CePdIn System

51%
Kratochvílová M., Custers J., Sechovský V.
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vol. 126
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issue 1
324-325
EN
We report on the investigation of recently discovered heavy fermion compounds within the Ce-Pd-In system. Single crystals of Ce_{n}Pd_{m}In_{3n+2m} (n=2, 3, 5; m=1, 2) and Ce_{4}Pd_{10}In_{21} were synthesized from In-flux. Specific heat measurements of the multiphase Ce_{n}Pd_{m}In_{3n+2m} system revealed a superconducting transition at T_{c}=0.69 K arising from Ce_{2}PdIn_{8} and another, magnetic transition at T_{m}=1.67 K arising from either Ce_{3}PdIn_{11} or Ce_{5}Pd_{2}In_{19}. Low-temperature data of Ce_{4}Pd_{10}In_{21} display ferromagnetic long-range order below 0.8 K.
17
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Intermolecular Effects of Fluorocarbons on MC800 Asphaltene and their Characterization

51%
Kirimli H., Ovalioglu H., Akay C.
Acta Physica Polonica A
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2017
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vol. 131
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issue 3
336-338
EN
Nuclear magnetic resonance and dynamic nuclear polarization experiments were performed to study suspensions of asphaltene in the fluorocarbons at a low magnetic field of 1.53 mT, at room temperature. The asphaltene was extracted from MC800 liquid asphalt, which was of Heavy Iran origin. The elemental composition and the surface morphology of the asphaltene were determined by scanning electron microscopy and energy dispersive X-ray analysis. Intermolecular spin-spin interactions occur between nuclear spins of hydrogen in the solvent medium and the free electron spins in the asphaltene micelles. The electron paramagnetic resonance spectrum of the asphaltene was obtained and the saturation experiments were applied to the samples prepared in vacuum. The main ¹H DNP parameters were listed. Chemical composition and molecular structure of the asphaltene were analyzed. Scanning electron microscope images have shown that asphaltenes are constituted of agglomerated particles and smooth surfaces. Energy dispersive X-ray analysis has shown that the most abundant element is carbon.
18
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Surface Characterization of 309 and 310 Steel after the Corrosion in Wood Biomass Ash

51%
Dębowska A., Kopia A., Kalemba-Rec I., Petrzak P., Magdziarz A.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1387-1389
EN
The aim of this study was to investigate the influence of biomass ashes - specifically wood biomass ash - on the surface of austenitic stainless steel 309 and 310. The process was carried out for 1000 h at 650°C. The microstructure and chemical composition of corrosion products were examined by scanning electron microscopy with energy dispersive spectroscopy analysis. Phase analysis of corrosion product were done by X-ray diffraction and ash composition was investigated by X-ray fluorescence. It was observed that wood biomass ash caused the corrosion of the steel surface. On the surface of the steels exposed to wood biomass ash the layer of corrosion products was observed, mostly chromium, nickel and iron oxide. The thickness of mill scale formed during the process was in the range of h=15-30 μm.
19
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High-Temperature Corrosion of Ni-Base Alloys by Waste Incineration Ashes

51%
Solecka M., Kusiński J., Kopia A., Rozmus-Górnikowska M., Radziszewska A.
Acta Physica Polonica A
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2016
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vol. 130
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issue 4
1045-1048
EN
Ni-Cr-Mo alloys, e.g. Inconel 625 and 686, exhibit high-temperature corrosion, oxidation and wear resistance. For this reason, these alloys are typically used as a coating material in different environments as effective solid-state diffusion barriers between the corrosive atmosphere and the base metal. To perform: the Ni-base weld overlays, without introducing too much Fe, a new welding technique called cold metal transfer was used. High-temperature corrosion of boiler parts during incineration of waste was investigated. Boiler tubes were coated with Inconel 625 and Inconel 686 nickel alloys and, after subjecting them to waste incineration ashes, they were examined by scanning electron microscopy with energy dispersive X-ray spectrometer to reveal different corrosion mechanisms and their causes. Results indicate a strong dependence of the boiler steel corrosion on anions in the incineration waste ash. X-ray diffraction characteristics of the scale showed that surface corrosion processes induce the formation of CrO₂, NiO. The presence of iron in the clad weld surface is conductive to the formation of the Fe₂O₃ oxide.
20
Content available remote

Synthesis and Characterization of ZnO Doped with Fe_{2}O_{3} - Hydrothermal Synthesis and Calcination Process

51%
Sibera D., Jędrzejewski R., Mizeracki J., Presz A., Narkiewicz U., Łojkowski W.
Acta Physica Polonica A
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2009
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vol. 116
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issue S
S-133-S-135
EN
The aim of the present work is to compare two methods of synthesis of nanocrystallline zinc oxide doped with iron oxide. The synthesis was carried out using microwave asssisted hydrothermal synthesis and traditional wet chemistry method followed by calcination. The phase composition of the samples was determined using X-ray diffraction measurements. Depending on the chemical composition of the samples, hexagonal ZnO, and/or cubic ZnFe_{2}O_{4} were identified. The morphology of the received materials was characterized using scanning electron microscopy. Two different structures of agglomerates were observed: a hexagonal structure (corresponding to zinc oxide) and spherical (corresponding to spinel phase). The effect of the iron oxide concentration on specific surface area and density of the samples was determined.
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