Katarzyna Berent | AGH University of Science and Technology (original) (raw)

Papers by Katarzyna Berent

The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were st... more The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were studied. Partial polarization curves were determined. The influence of applied potential, electrolyte composition and pH level, hydrodynamic conditions and quantity of charge passed, on the electrodeposition of Sn-Mn layers were determined. The surface composition of deposits was ascertained by chemical analysis (WDXRF). The morphology of coatings was studied by SEM. The phase composition of Sn-Mn samples was determined by X-ray diffractometry and Raman spectroscopy. The electrolysis parameters allowing electrodeposition of Sn-Mn coatings containing various amounts of Mn (in the range from about 0.5 wt% to 42 wt%) were selected. The morphology of deposits depends significantly on the content of manganese and on the parameters of electrolysis. The surface morphology of samples with Mn content of about 27 wt% is not uniform, two types of areas with significant differences in chemical composition are observed. XRD studies indicate that four crystallographic phases are formed in the deposits (β-Sn),MnO,Mn(OH)2, andMnSn2, while Raman spectroscopy revealed also the presence of α-MnO2, MnOOH, and SnO2, which are the products of chemical processes taking place simultaneously with electrolysis. The mechanism of the co-deposition of manganese with tin has been proposed.

IOP Conference Series: Materials Science and Engineering, 2014

Crystal lattice rotations induced by shear bands developed in an AA1050 aluminium alloy have been... more Crystal lattice rotations induced by shear bands developed in an AA1050 aluminium alloy have been examined in order to investigate the influence of the finegrained structure on the slip propagation across the grain boundaries and the resulting texture evolution. Samples of the AA1050 alloy were pre-deformed in ECAP up to 6 passes via route C, then machined and further compressed in a channel-die up to ~25% at room temperature. The microstructure and texture were characterized by SEM equipped with a high resolution EBSD facility.

Mikro-i nanoproszki 8% mol. Y 2 O 3 -ZrO 2 (8YSZ) wytworzono za pomocą metody wspóástrącania i kr... more Mikro-i nanoproszki 8% mol. Y 2 O 3 -ZrO 2 (8YSZ) wytworzono za pomocą metody wspóástrącania i krystalizacji w warunkach kalcynacji lub obróbki hydrotermalnej. Proszki wykorzystano do formowania cienkich folii metodą odlewania z gĊstwy (doctor blade method). Oznaczono gĊstoĞü pozorną, nasiąkliwoĞü i porowatoĞü otwartą folii elektrolitowych. Dyskusji poddano wpáyw warunków spiekania na mikro-strukturĊ otrzymanych folii.

Materials Science Forum, 2013

Early stages of recrystallization were observed for the technical purity aluminium alloy (AA1050)... more Early stages of recrystallization were observed for the technical purity aluminium alloy (AA1050). The samples were severely deformed by equal channel angular pressing and then annealed to obtain the state of partial recrystallization. The nucleation of new grains and the changes in 'density' of low-and high-angle boundaries were analysed using scanning electron microscopy equipped with high resolution EBSD system. After deformation in six passes along route A the alloy contained a structure of flat grains. On annealing, the structure coarsened and got transformed into nearly equiaxed grains by both discontinuous and continuous recrystallization. A particular role in the rise of nuclei and the structure spheroidization is attributed to migration of low-angle boundaries.

Journal of Materials Science, 2012

Wetting of Al (99 %) pads by Sn-8.8Zn, Sn-8.7Zn-1.5In, and Sn-8.7Zn-1.5Ag (wt%) alloys was studie... more Wetting of Al (99 %) pads by Sn-8.8Zn, Sn-8.7Zn-1.5In, and Sn-8.7Zn-1.5Ag (wt%) alloys was studied by means of the sessile drop method. The tests were carried out at 250°C, using Amasan ALU33Ò flux, for up to 60 min. We used a setup that allows fast transfer of a sample to and from the hot zone of the furnace. Solidified alloy-substrate couples were cross sectioned and examined by scanning electron microscopy and energy dispersive X-ray analysis. The studied alloys wet Al pads as the wetting angles, determined after cleaning the flux residue from solidified alloy-substrate couples, are lower than 35 degrees. Wetting angles of Sn-8.7Zn-1.5Ag (wt%) alloy are higher and wetting areas are smaller than those of the remaining alloys, possibly due to a small gap between the melting and test temperatures. There is no clear dependence of the wetting angle and spreading area on time.

Journal of Materials Engineering and Performance, 2014

Your article is protected by copyright and all rights are held exclusively by ASM International. ... more Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Ni-based alloys containing refractory metal (molybdenum or tungsten) characterized by high hardne... more Ni-based alloys containing refractory metal (molybdenum or tungsten) characterized by high hardness, high wear, thermal and corrosion resistance are widely used for many industrial applications as they offer an important alternative to toxic, hard chromium coatings. In the present work the formation of the amorphous Ni-W films by electrochemical deposition from aqueous baths at room temperature has been reported. The Ni-W alloys have been electrodeposited from sulphate-citrate electrolyte, under potentiostatic or potentiodynamic regimes. To ensure a steady and controlled hydrodynamic condition, a rotating disk electrode (RDE) system was used. It was observed that alloys electrodeposited at different cathode potentials vary in chemical composition and thickness. Such effect results mainly from kinetics of nickel and tungsten induced codeposition as well as on the decrease of the electrodeposition current efficiency as the cathode potential becomes more negative. Concentrations of elements in the electrodeposits were determined using energy-dispersive X-ray spectroscopy (EDS) in a scanning electron microscopy (SEM) with a thermally assisted Schottky field emission gun (FEG). Monte Carlo calculations for characteristic X-ray intensities emitted from coatings of given thicknesses and chemical compositions were used to evaluate the most adequate electron beam energy for X-ray emission. The results obtained are compared to chemical analyses carried out by the atomic absorption spectroscopy (AAS) technique.

Solid State Phenomena, 2012

ABSTRACT The nanocrystalline silver powder and the amorphous powders of composition Ni49,5Ti20,5N... more ABSTRACT The nanocrystalline silver powder and the amorphous powders of composition Ni49,5Ti20,5Nb15Zr15 (numbers indicate at%) were prepared by ball milling in the planetary Fritsch mill for 40 hours. TEM studies confirmed almost complete amorphization of milled alloys powders allowed to detect a small fraction of a small intermetallic inclusions within the amorphous matrix. The erosion of composites during contact cycling was similar as in Ag-W composites known as a good contact materials. SEM and TEM studies have shown a low solubility of tungsten in silver after ball milling and no solubility of silver in tungsten. The grain size of silver crystals within powders drastically decreased after milling down to about 30 nm and only a small increase in the grain size up to 200 nm was observed after hot pressing. These results were confirmed using TEM studies of composites after hot pressing. TEM microstructures have shown very narrow transition layer at the amorphous/silver interface (between 10-30 nm thick) containing all elements from the amorphous powders plus silver due to short time of hot pressing. The amorphous part has shown growth of intermetallic phases there, however diffused ring from the amorphous part was still visible. The composites prepared from silver and tungsten have shown presence of coherent tungsten rich precipitates showing typical strain field contrast within fine grains near 100 nm formed most probably during hot pressing of silver solid solution formed during mechanical alloying. The structure of tungsten has shown less defects and consequently less grain refinement than silver particles. SEM studies of the compression tested samples of silver-amorphous composites have shown crack formation at the interfaces of both components most probably due to presence of a brittle transition phase containing all elements.

Solid State Phenomena, 2012

a nmberent@imim-pan.krakow.pl, b nmfaryna@imim-pan.krakow.pl Abstract. Modern scanning electron m... more a nmberent@imim-pan.krakow.pl, b nmfaryna@imim-pan.krakow.pl Abstract. Modern scanning electron microscopes (SEMs) increase the ability to study a wide range of materials. Especially, an application of low vacuum conditions enables characterization of nonconductive samples without complicated preparation procedure. However, the operator must be aware of several problems he may encounter collecting electron diffractions in the SEM with variable pressure. The charge control and quality of the surface are the challenges when running experiments on insulators. Specimen charging obscures forward scatter electrons images and decreases the EBSD pattern quality making indexing difficult or even impossible. Another crucial question is how to limit the influence of so called "skirt effect" caused by ionization of gas molecules followed by electron beam broading above the sample. The influence of several important parameters (gas pressure, a type of gas, working distance and energy of electron beam) on the EBSD pattern quality must also be considered. When it is properly done, a coupling of crystallographic information with the chemical data obtained from Energy Dispersive Spectroscopy (EDS) in the LV-SEM allows to perform phase identification of insulators. The paper presents some ideas how to deal with the (Pb, La)(Zr, Ti)O 3 ceramics in high resolution Quanta 3D SEM (with thermally assisted Schottky type FEG) equipped with EDAX-TSL system in low vacuum environment. The problems occurring during EBSD analysis of the PLZT ceramics are discussed and some solutions are suggested. Paper summarizes the results obtained from PLZT ferroelectric ceramics in the low vacuum FEGSEM and shows how to optimise experimental parameters in order to achieve the best quality of orientation maps acquired from nonconductive samples.

Journal of the Electrochemical Society, 2014

The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were st... more The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were studied. Partial polarization curves were determined. The influence of applied potential, electrolyte composition and pH level, hydrodynamic conditions and quantity of charge passed, on the electrodeposition of Sn-Mn layers were determined. The surface composition of deposits was ascertained by chemical analysis (WDXRF). The morphology of coatings was studied by SEM. The phase composition of Sn-Mn samples was determined by X-ray diffractometry and Raman spectroscopy. The electrolysis parameters allowing electrodeposition of Sn-Mn coatings containing various amounts of Mn (in the range from about 0.5 wt% to 42 wt%) were selected. The morphology of deposits depends significantly on the content of manganese and on the parameters of electrolysis. The surface morphology of samples with Mn content of about 27 wt% is not uniform, two types of areas with significant differences in chemical composition are observed. XRD studies indicate that four crystallographic phases are formed in the deposits (β-Sn), MnO, Mn(OH) 2 , and MnSn 2 , while Raman spectroscopy revealed also the presence of α-MnO 2 , MnOOH, and SnO 2 , which are the products of chemical processes taking place simultaneously with electrolysis. The mechanism of the co-deposition of manganese with tin has been proposed.

Journal of Alloys and Compounds, 2014

ABSTRACT Electrodeposition process is a very promising method for producing metal matrix composit... more ABSTRACT Electrodeposition process is a very promising method for producing metal matrix composites reinforced with ceramic particles. In this method insoluble particles suspended in an electrolytic bath are embedded in a growing metal layer. This paper is focused on the investigations of the nickel matrix nanocomposite coatings with hard alpha-Al2O3 nano-particles, electrochemically deposited from modified Watts-type baths on steel substrates. The influence of various current densities on the microstructure, residual stresses, texture, hardness and corrosion resistance of the deposited nickel/alumina coatings was investigated. The surface morphology, cross sections of the coatings and distribution of the ceramic particles in the metal matrix were examined by scanning electron microscopy. The phase composition, residual stresses and preferred grain orientation of the coatings were characterized using X-ray diffraction techniques. The coating morphology revealed that alpha-Al2O3 particles show a distinct tendency to form agglomerates, approximately uniformly distributed into the nickel matrix.

Advanced microstructure characterization based on the development of new generations of computer-... more Advanced microstructure characterization based on the development of new generations of computer-controlled electron microscopes started with the beginning of XXI century. New technologies have improved spatial resolution and increased a rate of collecting and processing of large quantities of data. Orientation microscopy is nowadays a well-established technique for studying and quantifying microstructures and determining crystallographic orientations and topography by use of Electron BackScatter Diffraction (EBSD) in Scanning Electron Microscope (SEM) [e.g. 1]. The technique is based on the automatic acquisition and indexing of a set of diffraction patterns correlated with sample coordinates. EBSD has made an extensive contribution to the crystallographic and structural analyses of ceramics providing information on: absolute or relative grain orientations, misorientation angles, planes of grain boundaries, identification of unknown phases etc. The fully automated EBSD facilities in SEMs are nowadays commercially available and fairly common in materials characterization laboratories. However, EBSD spatial resolution during SEM measurements strongly depends on a type of electron gun as well as material being investigated, permitting only microstructures with features in the range down to ~100 nm to be "mapped". In order to overcome such problems, Orientation Mapping (OM) technique in transmission electron microscope (TEM), based on Convergent Beam Electron Diffraction (CBED) patterns, was developed [2, 3, 4]. Despite some restrictions, OM in TEM offers spatial resolution less than 10 nm and can be used for quantitative analysis of microstructures at nanoscale .

Archives of Metallurgy and Materials, 2000

Polycrystalline, high purity (99,995%) zinc ingot was subjected to KoBo type extrusion in room te... more Polycrystalline, high purity (99,995%) zinc ingot was subjected to KoBo type extrusion in room temperature. Material was extruded to form of a 2 mm diameter wire, extrusion die oscillated during process by an angle ±8 • at a frequency of 5 Hz and the extrusion speed was 0.5 mm/s. Final product was tested for tensile strength and yielded R 0,2 ≈ 150MPa and R m ≈ 250MPa. Microstructure of both extruded and initial materials was investigated by means of high resolution Electron Backscatter Diffraction (EBSD) in Quanta 3D FEG scanning electron microscope (SEM). Observations revealed that microstructure of extruded zinc sample is highly heterogeneous and consists of grains elongated slightly in the direction of extrusion. Grains dimensions ranges from over one hundred microns down to submicron scale while grains in the non-deformed material are equiaxed with mean diameter of approximately 200 microns. Other microstructure features such as intergranular bands and partly fragmented primary grains with subgrain structure are observed. Furthermore detailed study of local microstrains by Imaqe Quality Factor analysis are performed. Presence of Geometrically Necessary and Statistically Stored Dislocations is assessed. Thick areas of highly distorted lattice adjacent to High Angle Grain Boundaries are revealed. Microstrain mapping suggest composite-like microstructure of deformed material, that might explain its superior mechanical properties.

Applied Surface Science, 2009

Acta Materialia, 2005

The mechanical properties of Al 2 O 3 -based porous ceramics fabricated from pure Al 2 O 3 powder... more The mechanical properties of Al 2 O 3 -based porous ceramics fabricated from pure Al 2 O 3 powder and the mixtures with Al(OH) 3 were investigated. The fracture strength of the porous Al 2 O 3 specimens sintered from the mixture was substantially higher than that of the pure Al 2 O 3 sintered specimens because of strong grain bonding that resulted from the fine Al 2 O 3 grains produced by the decomposition of Al(OH) 3 . However, the elastic modulus of the porous Al 2 O 3 specimens did not increase with the incorporation of Al(OH) 3 , so that the strain to failure of the porous Al 2 O 3 ceramics increased considerably, especially in the specimens with high porosity, because of the unique pore structures related to the large original Al(OH) 3 particles. Fracture toughness also increased with the addition of Al(OH) 3 in the specimens with higher porosity. However, fracture toughness did not improve in the specimens with lower porosity because of the fracture-mode transition from intergranular, at higher porosity, to transgranular, at lower porosity.

IOP Conference Series: Materials Science and Engineering, 2014

Materials Science Forum, 2013

Journal of Materials Science, 2012

Journal of Materials Engineering and Performance, 2014

Solid State Phenomena, 2012

Journal of the Electrochemical Society, 2014

The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were st... more The conditions for manganese with tin electrodeposition from aqueous citrate electrolytes were studied. Partial polarization curves were determined. The influence of applied potential, electrolyte composition and pH level, hydrodynamic conditions and quantity of charge passed, on the electrodeposition of Sn-Mn layers were determined. The surface composition of deposits was ascertained by chemical analysis (WDXRF). The morphology of coatings was studied by SEM. The phase composition of Sn-Mn samples was determined by X-ray diffractometry and Raman spectroscopy. The electrolysis parameters allowing electrodeposition of Sn-Mn coatings containing various amounts of Mn (in the range from about 0.5 wt% to 42 wt%) were selected. The morphology of deposits depends significantly on the content of manganese and on the parameters of electrolysis. The surface morphology of samples with Mn content of about 27 wt% is not uniform, two types of areas with significant differences in chemical composition are observed. XRD studies indicate that four crystallographic phases are formed in the deposits (β-Sn), MnO, Mn(OH) 2 , and MnSn 2 , while Raman spectroscopy revealed also the presence of α-MnO 2 , MnOOH, and SnO 2 , which are the products of chemical processes taking place simultaneously with electrolysis. The mechanism of the co-deposition of manganese with tin has been proposed.

Journal of Alloys and Compounds, 2014

Archives of Metallurgy and Materials, 2000

Applied Surface Science, 2009

Acta Materialia, 2005