P. Indyka | Jagiellonian University in Krakow (original) (raw)

Papers by P. Indyka

Praca dotyczy problemu poszukiwań substytutu twardych powłok chromowych w odpowiedzi na potrzeby ... more Praca dotyczy problemu poszukiwań substytutu twardych powłok chromowych w odpowiedzi na potrzeby przemysłu lotniczego i samochodowego, co wiąże się z koniecznością opracowania nowych kąpieli elektrolitycznych neutralnych dla środowiska naturalnego, mogących zastąpić stosowane dotąd toksyczne roztwory elektrolitów zawierające Cr(VI). Celem prowadzonych prac badawczych było wskazanie drogi optymalizacji mikrostruktury powłok stopu Ni-W poprzez odpowiednie sterowanie procesem galwanicznym w kierunku podwyższenia właściwości funkcjonalnych powłok, decydujących o ich praktycznym zastosowaniu. W pracy przedstawiono wyniki badań prowadzących do zaprojektowania kąpieli galwanicznej o optymalnym składzie (modelowanie równowagowego składu elektrolitu), opisano zależności kinetyczne, oraz charakterystykę mikrostrukturalną powłok stopu Ni-W osadzanych w różnych warunkach prądowo-napięciowych. Badania mikrostrukturalne powłok Ni-W wykonano przy wykorzystaniu

Nanoscale, 2020

Comprehensive and systematic experimental studies of the Au interactions with the AIII-BV surface... more Comprehensive and systematic experimental studies of the Au interactions with the AIII-BV surface at the atomic level with chemical sensitivity shed new light on the fundamental Au/AIII-BV interactions at the atomic scale.

Applied Catalysis B: Environmental, 2021

The K-Zn x Co 3-x O 4 catalyst supported on α-Al 2 O 3 for N 2 O decomposition was investigated i... more The K-Zn x Co 3-x O 4 catalyst supported on α-Al 2 O 3 for N 2 O decomposition was investigated in terms of its resistance towards typical contaminants (O 2 , H 2 O, and NO) present in the nitric acid plant tail gases. The catalyst synthesized in laboratory-scale was thoroughly characterized by means of X-ray μ-tomography, XRF, XRD, and SEM/TEM/EDX. The impact of contaminants such as O 2 , H 2 O, and NO on the N 2 O conversion of the catalyst was examined and quantified by kinetic and thermodynamic modeling. The mechanism of inhibition involving local (active site blocking) and global (modification of the spinel electronic properties by electrophilic NO x adspecies) effects was proposed. The strongest inhibition of NO was associated with its facile reactivity with surface O intermediates produced during N 2 O decomposition. The resultant NO 2 and NO 3 surface adducts are stable at the catalyst surface up to 550 • C. For the pilot catalyst, the effect of contamination was the same in nature as for the laboratory sample, however, the observed quantitative differences were associated with the changes in the shape of the spinel nanocrystals constituting the catalyst active phase. The obtained results provide rationales for designing and preparation of the robust deN 2 O catalyst with enhanced resistivity to poisoning.

International Journal of Hydrogen Energy, 2020

h i g h l i g h t s g r a p h i c a l a b s t r a c t Improvement of cobalt-based catalyst activi... more h i g h l i g h t s g r a p h i c a l a b s t r a c t Improvement of cobalt-based catalyst activity in the ESR process upon K addition. Enhancement of the catalyst stability and selectivity in the ESR process. The strong influence of K on the cobalt-alumina interaction and Co dispersion. Increase of the catalyst acidity

Materials Today Sustainability, 2020

We have synthesized and characterized a series of TiO 2 (B)/anatase photocatalysts in the form of... more We have synthesized and characterized a series of TiO 2 (B)/anatase photocatalysts in the form of nanobelts. Spectroelectrochemical measurements (SE-DRS) revealed the staggered type of the band alignment for anatase and TiO 2 (B) composites, with higher potentials of band edges for anatase. The photoactivity of the materials and photocurrent generation have been studied. Similarly to anatase/rutile composites, a synergistic effect of the presence of two phases has been observed for TiO 2 (B)/anatase (2:98) material in the reaction of hydroxyl radicals generation. In the case of hydrogen generation reaction, such synergy was not noticed, likewise in the case of IPCE measurements. On the other hand, singlet oxygen generation takes place preferably at TiO 2 (B), despite worse oxygen adsorption at this polymorph. Our findings shed new light on the general understanding of the photocatalytic activity of TiO 2 (B) and its composites with anatase. Unlike suggested elsewhere, instead of facilitating hydrogen evolution reaction, TiO 2 (B), as a minor admixture, should rather be considered as a component of photocatalysts optimized for oxidation reactions involving hydroxyl radicals.

Materials Characterization, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Applied Catalysis B: Environmental, 2019

Supported Co 3 O 4 and Co 4 MnAlO x mixed oxides were prepared by deposition on the SiC open-cell... more Supported Co 3 O 4 and Co 4 MnAlO x mixed oxides were prepared by deposition on the SiC open-cell foams by wet impregnation and suspension methods and characterized by AAS, BET, XRD, SEM, TEM, TPR-H 2 , XPS and nitrogen adsorption methods. Prepared supported catalysts as well as active phase Co 3 O 4 and Co 4 MnAlO x in grain form prepared from parent solutions were tested for nitrous oxide decomposition. Catalytic activity of grain active phase was governed by methods of preparation; Co 3 O 4 and Co 4 MnAlO x prepared by suspension method were significantly more active than those from solutions for impregnation method. Suspension method provided active phase with higher surface areas and sites with better reducibility, both of these factors contributed to higher N 2 O conversions. In contrast to this, N 2 O conversions over supported catalysts were dependent more on chemical composition of active phase than on method of preparation. Both catalysts containing Co 4 MnAlO x mixed oxide revealed higher conversion of N 2 O than catalysts containing Co 3 O 4. STEM analysis of the most active Co 4 MnAlO x prepared by suspension method showed (i) segregation of Co 3 O 4 nanocrystals of cuboctahedral shape containing (100) and (111) facets (this segregation was confirmed also by XPS and TPR-H 2) and (ii) Co-Mn-Al oxide nanoparticles with very small un-faceted grains assembled into elongated fiber-like agglomerates were observed by STEM.

Fuel, 2019

Abstract The course of pyrolysis process of the three industrial samples of lower, middle, and hi... more Abstract The course of pyrolysis process of the three industrial samples of lower, middle, and higher rank coals was studied using the TG/FT-IR technique and a laboratory unit for investigation of carbonization process by X-raying. The coal samples from the zones of plastic layer were studied by scanning electron microscopy and next extracted by a mixture of chloroform and methanol. The obtained extracts were analyzed by FT-IR and UV spectroscopies and STEM-HAADF technique. It was stated that the composition of volatile products of a lower rank coal (LRC) is characterized by the greatest relative content of saturated and unsaturated hydrocarbons in comparison with a middle rank coal (MRC) and a higher rank coal (HRC). However, a higher contribution ratio of water vapour is observed in the composition of volatile matter of HRC. It is suggested that low molecular products of destruction formed inside swelling grains of MRC can react with each other and form new compounds with a greater molecular mass. These can be macromolecules of heteroorganic compounds. The STEM-HAADF images showed that there are topological structures of various types in the material of extracts from the gas-saturated zone of coals of different rank. The presence of inorganic elements in the extracted material changes depending on coal rank. Heterorganic compounds of different shape and composition can catalyze the reactions taking place during thermal destruction of coals in a selective way. In MRC, these reactions will cause a decrease in pressure inside its swelling grains and without their substantial growth in volume. Such reactions do not take place in grains of HRC. Moreover, an increased contribution of water vapour formed during destruction can cause its adsorption inside grains and an increase in volume of swelling grains. This can be the cause for an increase in generation of dangerous coking pressure in the charge of studied HRC.

Materials Characterization, 2018

SiO 2 /Ni nanocomposite coatings containing well-dispersed SiO 2 nanoparticles were electrodeposi... more SiO 2 /Ni nanocomposite coatings containing well-dispersed SiO 2 nanoparticles were electrodeposited from a sulphate bath with and without the addition of polyethylenimine (PEI) as a cationic surfactant. The surface morphology and microstructure in the cross-sections of the deposited nanocomposites were examined by scanning electron microscopy. More detailed microstructure characterization was performed using transmission, scanning-transmission and high resolution transmission electron microscopy. It was determined that the addition of 0.05 g/L and 0.1 g/L of PEI allows the incorporation of SiO 2 nanoparticles in the nickel matrix to be increased in comparison with the nanocomposite deposited without a surfactant. Based on high spatial resolution microanalysis, performed using high count rate energy dispersive spectroscopy of characteristic X-rays in the scanning-transmission mode, the distribution of SiO 2 nanoparticles in the nanocomposite was visualized on elemental maps. Image analysis of the electron microscopy images enabled the mean equivalent circle diameters of grains in the nickel matrix to be determined, together with the volume fraction of SiO 2 nanoparticles in the nanocomposites. The volume fraction of SiO 2 clusters in the SiO 2 /Ni + PEI nanocomposites with the addition of 0.05 g/L and 0.1 g/L of PEI is equal to 18.4% and 13.3%, respectively. Furthermore, the PEI addition allows the nickel grain size in the matrix to be reduced. The combination of different imaging techniques confirmed that PEI is not only present as a surfactant in the electrolytic bath, but also incorporates into the microstructure of the nanocomposite. Nanocomposites electrodeposited in the presence of 0.05 g/L of PEI exhibit higher hardness, good tribological properties and improved corrosion resistance. Although increasing the PEI concentration in the bath up to 0.1 g/L strongly promotes grain size reduction and increase of the SiO 2 volume fraction, it also causes an increase in the PEI fraction embedded in the microstructure, which results in deterioration of the properties of the SiO 2 /Ni + PEI nanocomposites.

Acta Physica Polonica A, 2017

The aim of the present work is to investigate the development of the γ/γ microstructure and the c... more The aim of the present work is to investigate the development of the γ/γ microstructure and the changes in chemical composition of γ and γ phases during high temperature annealing of CMSX-4 superalloy at a temperature of 1100 • C in the time range from 500 to 2500 h. The studies were performed by means of scanning electron microscopy and the modern scanning-transmission electron microscopy with Super-X EDS system of four SDD detectors. Results of scanning electron microscopy and scanning-transmission electron microscopy analyses have shown that the microstructure of CMSX-4 superalloy is unstable during ageing at high temperature and the coalescence of cuboidal γ precipitates was observed. Energy dispersive X-ray microanalysis revealed the distribution of particular alloying elements in the γ and γ phases and the differences in their concentration in the function of the annealing time.

Journal of Microscopy, 2017

A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and s... more A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanningtransmission electron microscopy (STEM) using high-angle annular-dark-field (HAADF) imaging, focussed ion beamscanning electron microscopy (FIB-SEM) tomography, selected area electron diffraction with beam precession (PED), as well as spatially resolved energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), was used to investigate topologically close-packed (TCP) phases, occurring in the CMSX-4 superalloy subjected to high temperature annealing and creep deformation. Structural and chemical analyses were performed to identify the TCP phases and provide information concerning the compositional partitioning of elements between them. The results of SEM and FIB-SEM tomography revealed the presence of merged TCP particles, which were identified by TEM and PED analysis as coprecipitates of the μ and P phases. Inside the TCP particles that were several micrometres in size, platelets of alternating μ and P phases of nanometric width were found. The combination of STEM-HAADF imaging with spatially resolved EDS and EELS microanalysis allowed determination of the significant partitioning of the constituent elements between the μ and P phases.

Journal of Electroanalytical Chemistry, 2016

Ni-W/ZrO 2 nanocomposite coatings were electrodeposited in a system with a rotating disk electrod... more Ni-W/ZrO 2 nanocomposite coatings were electrodeposited in a system with a rotating disk electrode (RDE), which ensures constant and controlled hydrodynamic conditions. The influence of solution chemistry on the co-discharge kinetics of W(VI) and Ni(II) species from citrate solution have been studied. It was found that in the range of less negative cathode potentials both partial processes (deposition of tungsten and nickel) are controlled by charge transfer reaction, whereas with further increase of the cathodic polarisation the W(VI) electroreduction process becomes diffusion controlled. The addition of ceramic particles to the alloy plating bath changes cathodic polarization, and thus chemical composition of the deposited Ni-W matrix. The effect of rotating rate of the steel RDE on the chemical composition and homogeneity of embedded zirconia nanoparticles in the Ni-W alloy matrix was investigated. The optimal hydrodynamic conditions for electrodeposition of

Materials Chemistry and Physics, 2016

Abstract Ni–W/ZrO 2 nanocomposite coatings were electrodeposited on steel substrates in a system ... more Abstract Ni–W/ZrO 2 nanocomposite coatings were electrodeposited on steel substrates in a system with a rotating disk electrode (RDE). The effect of current density of the plating process on the chemical composition, microstructure and physicochemical properties of resulting composites was studied. Based on microstructural (morphology, phase composition, crystallite size), micromechanical (microhardness, Young's modulus), tribological (wear resistant, friction coefficient) and corrosion (corrosion potential, corrosion current density) properties, the optimal direct current (DC) density range for electrodeposition of homogeneous Ni–W/ZrO 2 nanocomposites with enhanced functional properties was determined.

Topics in Catalysis, 2016

Iron-based FBC additives with a different length of the organic stabilizing ligands: undecylenic ... more Iron-based FBC additives with a different length of the organic stabilizing ligands: undecylenic acid (C11) and oleic acid (C18) were synthesized. A physicochemical characterization of the materials structure and morphology was performed by means of Raman spectroscopy, electron diffraction and TEM imaging. It was found that the reactivity of iron-based fuel borne catalysts depends on the length of the organic disperser and the size of the formed hematite nanoparticles. Reactivity tests performed in soot oxidation reaction both at a laboratory scale and in a commercial light oil burner revealed that the C11 stabilizer is more efficient than the C18 one in decreasing the emission of CO and soot particles.

Praca dotyczy problemu poszukiwań substytutu twardych powłok chromowych w odpowiedzi na potrzeby ... more Praca dotyczy problemu poszukiwań substytutu twardych powłok chromowych w odpowiedzi na potrzeby przemysłu lotniczego i samochodowego, co wiąże się z koniecznością opracowania nowych kąpieli elektrolitycznych neutralnych dla środowiska naturalnego, mogących zastąpić stosowane dotąd toksyczne roztwory elektrolitów zawierające Cr(VI). Celem prowadzonych prac badawczych było wskazanie drogi optymalizacji mikrostruktury powłok stopu Ni-W poprzez odpowiednie sterowanie procesem galwanicznym w kierunku podwyższenia właściwości funkcjonalnych powłok, decydujących o ich praktycznym zastosowaniu. W pracy przedstawiono wyniki badań prowadzących do zaprojektowania kąpieli galwanicznej o optymalnym składzie (modelowanie równowagowego składu elektrolitu), opisano zależności kinetyczne, oraz charakterystykę mikrostrukturalną powłok stopu Ni-W osadzanych w różnych warunkach prądowo-napięciowych. Badania mikrostrukturalne powłok Ni-W wykonano przy wykorzystaniu

Nanoscale, 2020

Comprehensive and systematic experimental studies of the Au interactions with the AIII-BV surface... more Comprehensive and systematic experimental studies of the Au interactions with the AIII-BV surface at the atomic level with chemical sensitivity shed new light on the fundamental Au/AIII-BV interactions at the atomic scale.

Applied Catalysis B: Environmental, 2021

The K-Zn x Co 3-x O 4 catalyst supported on α-Al 2 O 3 for N 2 O decomposition was investigated i... more The K-Zn x Co 3-x O 4 catalyst supported on α-Al 2 O 3 for N 2 O decomposition was investigated in terms of its resistance towards typical contaminants (O 2 , H 2 O, and NO) present in the nitric acid plant tail gases. The catalyst synthesized in laboratory-scale was thoroughly characterized by means of X-ray μ-tomography, XRF, XRD, and SEM/TEM/EDX. The impact of contaminants such as O 2 , H 2 O, and NO on the N 2 O conversion of the catalyst was examined and quantified by kinetic and thermodynamic modeling. The mechanism of inhibition involving local (active site blocking) and global (modification of the spinel electronic properties by electrophilic NO x adspecies) effects was proposed. The strongest inhibition of NO was associated with its facile reactivity with surface O intermediates produced during N 2 O decomposition. The resultant NO 2 and NO 3 surface adducts are stable at the catalyst surface up to 550 • C. For the pilot catalyst, the effect of contamination was the same in nature as for the laboratory sample, however, the observed quantitative differences were associated with the changes in the shape of the spinel nanocrystals constituting the catalyst active phase. The obtained results provide rationales for designing and preparation of the robust deN 2 O catalyst with enhanced resistivity to poisoning.

International Journal of Hydrogen Energy, 2020

h i g h l i g h t s g r a p h i c a l a b s t r a c t Improvement of cobalt-based catalyst activi... more h i g h l i g h t s g r a p h i c a l a b s t r a c t Improvement of cobalt-based catalyst activity in the ESR process upon K addition. Enhancement of the catalyst stability and selectivity in the ESR process. The strong influence of K on the cobalt-alumina interaction and Co dispersion. Increase of the catalyst acidity

Materials Today Sustainability, 2020

We have synthesized and characterized a series of TiO 2 (B)/anatase photocatalysts in the form of... more We have synthesized and characterized a series of TiO 2 (B)/anatase photocatalysts in the form of nanobelts. Spectroelectrochemical measurements (SE-DRS) revealed the staggered type of the band alignment for anatase and TiO 2 (B) composites, with higher potentials of band edges for anatase. The photoactivity of the materials and photocurrent generation have been studied. Similarly to anatase/rutile composites, a synergistic effect of the presence of two phases has been observed for TiO 2 (B)/anatase (2:98) material in the reaction of hydroxyl radicals generation. In the case of hydrogen generation reaction, such synergy was not noticed, likewise in the case of IPCE measurements. On the other hand, singlet oxygen generation takes place preferably at TiO 2 (B), despite worse oxygen adsorption at this polymorph. Our findings shed new light on the general understanding of the photocatalytic activity of TiO 2 (B) and its composites with anatase. Unlike suggested elsewhere, instead of facilitating hydrogen evolution reaction, TiO 2 (B), as a minor admixture, should rather be considered as a component of photocatalysts optimized for oxidation reactions involving hydroxyl radicals.

Materials Characterization, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Applied Catalysis B: Environmental, 2019

Supported Co 3 O 4 and Co 4 MnAlO x mixed oxides were prepared by deposition on the SiC open-cell... more Supported Co 3 O 4 and Co 4 MnAlO x mixed oxides were prepared by deposition on the SiC open-cell foams by wet impregnation and suspension methods and characterized by AAS, BET, XRD, SEM, TEM, TPR-H 2 , XPS and nitrogen adsorption methods. Prepared supported catalysts as well as active phase Co 3 O 4 and Co 4 MnAlO x in grain form prepared from parent solutions were tested for nitrous oxide decomposition. Catalytic activity of grain active phase was governed by methods of preparation; Co 3 O 4 and Co 4 MnAlO x prepared by suspension method were significantly more active than those from solutions for impregnation method. Suspension method provided active phase with higher surface areas and sites with better reducibility, both of these factors contributed to higher N 2 O conversions. In contrast to this, N 2 O conversions over supported catalysts were dependent more on chemical composition of active phase than on method of preparation. Both catalysts containing Co 4 MnAlO x mixed oxide revealed higher conversion of N 2 O than catalysts containing Co 3 O 4. STEM analysis of the most active Co 4 MnAlO x prepared by suspension method showed (i) segregation of Co 3 O 4 nanocrystals of cuboctahedral shape containing (100) and (111) facets (this segregation was confirmed also by XPS and TPR-H 2) and (ii) Co-Mn-Al oxide nanoparticles with very small un-faceted grains assembled into elongated fiber-like agglomerates were observed by STEM.

Fuel, 2019

Abstract The course of pyrolysis process of the three industrial samples of lower, middle, and hi... more Abstract The course of pyrolysis process of the three industrial samples of lower, middle, and higher rank coals was studied using the TG/FT-IR technique and a laboratory unit for investigation of carbonization process by X-raying. The coal samples from the zones of plastic layer were studied by scanning electron microscopy and next extracted by a mixture of chloroform and methanol. The obtained extracts were analyzed by FT-IR and UV spectroscopies and STEM-HAADF technique. It was stated that the composition of volatile products of a lower rank coal (LRC) is characterized by the greatest relative content of saturated and unsaturated hydrocarbons in comparison with a middle rank coal (MRC) and a higher rank coal (HRC). However, a higher contribution ratio of water vapour is observed in the composition of volatile matter of HRC. It is suggested that low molecular products of destruction formed inside swelling grains of MRC can react with each other and form new compounds with a greater molecular mass. These can be macromolecules of heteroorganic compounds. The STEM-HAADF images showed that there are topological structures of various types in the material of extracts from the gas-saturated zone of coals of different rank. The presence of inorganic elements in the extracted material changes depending on coal rank. Heterorganic compounds of different shape and composition can catalyze the reactions taking place during thermal destruction of coals in a selective way. In MRC, these reactions will cause a decrease in pressure inside its swelling grains and without their substantial growth in volume. Such reactions do not take place in grains of HRC. Moreover, an increased contribution of water vapour formed during destruction can cause its adsorption inside grains and an increase in volume of swelling grains. This can be the cause for an increase in generation of dangerous coking pressure in the charge of studied HRC.

Materials Characterization, 2018

SiO 2 /Ni nanocomposite coatings containing well-dispersed SiO 2 nanoparticles were electrodeposi... more SiO 2 /Ni nanocomposite coatings containing well-dispersed SiO 2 nanoparticles were electrodeposited from a sulphate bath with and without the addition of polyethylenimine (PEI) as a cationic surfactant. The surface morphology and microstructure in the cross-sections of the deposited nanocomposites were examined by scanning electron microscopy. More detailed microstructure characterization was performed using transmission, scanning-transmission and high resolution transmission electron microscopy. It was determined that the addition of 0.05 g/L and 0.1 g/L of PEI allows the incorporation of SiO 2 nanoparticles in the nickel matrix to be increased in comparison with the nanocomposite deposited without a surfactant. Based on high spatial resolution microanalysis, performed using high count rate energy dispersive spectroscopy of characteristic X-rays in the scanning-transmission mode, the distribution of SiO 2 nanoparticles in the nanocomposite was visualized on elemental maps. Image analysis of the electron microscopy images enabled the mean equivalent circle diameters of grains in the nickel matrix to be determined, together with the volume fraction of SiO 2 nanoparticles in the nanocomposites. The volume fraction of SiO 2 clusters in the SiO 2 /Ni + PEI nanocomposites with the addition of 0.05 g/L and 0.1 g/L of PEI is equal to 18.4% and 13.3%, respectively. Furthermore, the PEI addition allows the nickel grain size in the matrix to be reduced. The combination of different imaging techniques confirmed that PEI is not only present as a surfactant in the electrolytic bath, but also incorporates into the microstructure of the nanocomposite. Nanocomposites electrodeposited in the presence of 0.05 g/L of PEI exhibit higher hardness, good tribological properties and improved corrosion resistance. Although increasing the PEI concentration in the bath up to 0.1 g/L strongly promotes grain size reduction and increase of the SiO 2 volume fraction, it also causes an increase in the PEI fraction embedded in the microstructure, which results in deterioration of the properties of the SiO 2 /Ni + PEI nanocomposites.

Acta Physica Polonica A, 2017

The aim of the present work is to investigate the development of the γ/γ microstructure and the c... more The aim of the present work is to investigate the development of the γ/γ microstructure and the changes in chemical composition of γ and γ phases during high temperature annealing of CMSX-4 superalloy at a temperature of 1100 • C in the time range from 500 to 2500 h. The studies were performed by means of scanning electron microscopy and the modern scanning-transmission electron microscopy with Super-X EDS system of four SDD detectors. Results of scanning electron microscopy and scanning-transmission electron microscopy analyses have shown that the microstructure of CMSX-4 superalloy is unstable during ageing at high temperature and the coalescence of cuboidal γ precipitates was observed. Energy dispersive X-ray microanalysis revealed the distribution of particular alloying elements in the γ and γ phases and the differences in their concentration in the function of the annealing time.

Journal of Microscopy, 2017

A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and s... more A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanningtransmission electron microscopy (STEM) using high-angle annular-dark-field (HAADF) imaging, focussed ion beamscanning electron microscopy (FIB-SEM) tomography, selected area electron diffraction with beam precession (PED), as well as spatially resolved energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), was used to investigate topologically close-packed (TCP) phases, occurring in the CMSX-4 superalloy subjected to high temperature annealing and creep deformation. Structural and chemical analyses were performed to identify the TCP phases and provide information concerning the compositional partitioning of elements between them. The results of SEM and FIB-SEM tomography revealed the presence of merged TCP particles, which were identified by TEM and PED analysis as coprecipitates of the μ and P phases. Inside the TCP particles that were several micrometres in size, platelets of alternating μ and P phases of nanometric width were found. The combination of STEM-HAADF imaging with spatially resolved EDS and EELS microanalysis allowed determination of the significant partitioning of the constituent elements between the μ and P phases.

Journal of Electroanalytical Chemistry, 2016

Ni-W/ZrO 2 nanocomposite coatings were electrodeposited in a system with a rotating disk electrod... more Ni-W/ZrO 2 nanocomposite coatings were electrodeposited in a system with a rotating disk electrode (RDE), which ensures constant and controlled hydrodynamic conditions. The influence of solution chemistry on the co-discharge kinetics of W(VI) and Ni(II) species from citrate solution have been studied. It was found that in the range of less negative cathode potentials both partial processes (deposition of tungsten and nickel) are controlled by charge transfer reaction, whereas with further increase of the cathodic polarisation the W(VI) electroreduction process becomes diffusion controlled. The addition of ceramic particles to the alloy plating bath changes cathodic polarization, and thus chemical composition of the deposited Ni-W matrix. The effect of rotating rate of the steel RDE on the chemical composition and homogeneity of embedded zirconia nanoparticles in the Ni-W alloy matrix was investigated. The optimal hydrodynamic conditions for electrodeposition of

Materials Chemistry and Physics, 2016

Abstract Ni–W/ZrO 2 nanocomposite coatings were electrodeposited on steel substrates in a system ... more Abstract Ni–W/ZrO 2 nanocomposite coatings were electrodeposited on steel substrates in a system with a rotating disk electrode (RDE). The effect of current density of the plating process on the chemical composition, microstructure and physicochemical properties of resulting composites was studied. Based on microstructural (morphology, phase composition, crystallite size), micromechanical (microhardness, Young's modulus), tribological (wear resistant, friction coefficient) and corrosion (corrosion potential, corrosion current density) properties, the optimal direct current (DC) density range for electrodeposition of homogeneous Ni–W/ZrO 2 nanocomposites with enhanced functional properties was determined.

Topics in Catalysis, 2016

Iron-based FBC additives with a different length of the organic stabilizing ligands: undecylenic ... more Iron-based FBC additives with a different length of the organic stabilizing ligands: undecylenic acid (C11) and oleic acid (C18) were synthesized. A physicochemical characterization of the materials structure and morphology was performed by means of Raman spectroscopy, electron diffraction and TEM imaging. It was found that the reactivity of iron-based fuel borne catalysts depends on the length of the organic disperser and the size of the formed hematite nanoparticles. Reactivity tests performed in soot oxidation reaction both at a laboratory scale and in a commercial light oil burner revealed that the C11 stabilizer is more efficient than the C18 one in decreasing the emission of CO and soot particles.