prof. dr hab. inż. Kazimierz Darowicki
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total: 435
Catalog Publications
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Theoretical description of the measuring method of instantaneous impedance spectra
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Influence of the boron doping level on the electrochemical oxidation of the azo dyes at Si/BDD thin film electrodes
PublicationIn this study the efficiency of electrochemical oxidation of aromatic pollutants, such as reactive dyes, at boron-doped diamond on silicon (Si/BDD) electrodes was investigated. The level of [B]/[C] ratio which is effective for the degradation and mineralization of selected aromatic pollutants, and the impact of [B]/[C] ratio on the crystalline structure, layer conductivity and relative sp3/sp2 coefficient of a BDD electrode were...
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Evaluation of corrosion inhibition of brass-118 in artificial seawater by benzotriazole using Dynamic EIS
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Dynamic electrochemical impedance spectroscopy of the first order electrode reaction
PublicationCiągłe transformaty STFT sinusoidalnego sygnału pobudzenia i odpowiedzi prądowej zostały wyznaczone dla reakcji elektrodowej pierwszego rzędu. Wyznaczono impedancję elektrody w łącznej dziedzinie czasu i częstotliwości. Wykonano pomiary dla reakcji redukcji Cd(II) na rtęciowej elektrodzie kroplowej w funkcji potencjału. Przedstawiono możliwość wyznaczenia chwilowych widm impedancyjnych. Opisano zależność rezystancji przeniesienia...
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Instantaneous impedance spectra of a non-stationary model electrical system
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Influence of water salinity on corrosion risk - the case of the southern Baltic Sea coast.
PublicationWater corrosivity in Gdansk Bay, Poland, the southern part of the Baltic Sea, was investigated. The analysed region is heavily industrialized, and the coastline is very diverse. Twenty-seven test points along the coastline were selected. Water parameters such as salinity, total dissolved solids content, resistivity, conductivity, oxygenation, pH and corrosion rate were determined. The results of the investigation are presented....
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Selection of measurement frequency in Mott–Schottky analysis of passive layer on nickel
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Investigation of pitting corrosion of stainless steel by means of acoustic emission and potentiodynamic methods
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Evaluation of pitting corrosion by means of dynamic electrochemical impedance spectroscopy
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Effect of native air-formed oxidation on the corrosion behavior of AA 7075 aluminum alloys
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The amplitude analysis of impedance spectra
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Impedance characterization of the process of polyaniline first redox transformation after aniline electropolymerization
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Study on surface termination of boron-doped diamond electrodes under anodic polarization in H2SO4 by means of dynamic impedance technique
PublicationAnodic oxidation is a popular way to modify termination bonds at boron doped diamond electrodes altering their electrochemical and physicochemical properties. Our studies, performed with dynamic electrochemical impedance spectroscopy technique, supported with X-ray photoelectron spectroscopy and ellipsometry analysis prove its utility in continuous on-line monitoring of impedance changes on the electrode surface under polarization...
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Investigation of the electrochemical behaviour of AA1050 aluminium alloy in aqueous alkaline solutions using Dynamic Electrochemical Impedance Spectroscopy
PublicationThe paper presents the electrochemical behaviour of aluminium alloy AA1050 in aqueous alkaline media in the pH range 14–8.5. Electrochemical study was applied in order to obtain comprehensive information on the mechanism and kinetics of the process of anodic dissolution of aluminium, supplemented by monitoring of surface topography using an electron microscope. The corrosion rate of AA1050 increases with increasing concentration...
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Evaluation of cavitation erosion–corrosion degradation of mild steel by means of dynamic impedance spectroscopy in galvanostatic mode
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Diamond-Phase (Sp3-C) Rich Boron-Doped Carbon Nanowalls (Sp2-C): A Physico-Chemical And Electrochemical Properties
PublicationThe growth of B-CNW with different boron doping levels controlled by the [B]/[C] ratio in plasma, and the influence of boron on the obtained material’s structure, surface morphology, electrical properties and electrochemical parameters, such as -ΔE and k°, were investigated. The fabricated boron-doped carbon nanowalls exhibit activity towards ferricyanide redox couple, reaching the peak separation value of only 85 mV. The flatband...
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Investigation effect of benzotriazole on the corrosion of brass-MM55 alloy in artificial seawater by dynamic EIS
PublicationW pracy przedstawiono wyniki badań impedancyjnych otrzymanych podczas ekspozycji stopu MM55 w środowisku sztucznej wody morskiej. Wykazano ścisłą korelację charakterystyk impedancyjnych ze stężeniem benzotriazolu. Przedstawiono czasową ewolucję ochronnego efektu inhibicyjnego.
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Corrosion rate measurements by non-linear electrochemical impedance spectroscopy
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Impedance investigation of passive 304 stainless steel in the pit pre-initiation state
PublicationZaprezentowano wyniki badań impedancyjnych stali stopowej 304L metodą klasycznej EIS i dynamicznej EIS. Badania związane były z przejściem stali stopowej ze stanu pasywnego do inicjacji powstawania wżerów. Na podstawie zmian parametrów elektrycznego schematu zastępczego stwierdzono, że najbardziej prawdopodobnym mechanizmem tworzenia się wżerów jest model zniszczenia (pęknięcia) warstwy pasywnej.
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Accelerated ageing of organic coating systems by thermal treatment
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Water uptake in protective organic coatings and its reflection in measured coating impedance
PublicationWater uptake in commercially available epoxy coating on mild steel using impedance spectroscopy and gravimetry was studied. The water content in the coating was determined using the Brasher-Kingsbury equation and various methods of coating capacitance calculation used in the literature. The obtained results were compared with reference gravimetric data. An overestimation of values obtained from impedance data in relation to gravimetric...
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Investigations of the passive layer cracking by means of Dynamic Electrochemical Impedance Spectroscopy
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A new time-frequency detection method of stray current field interferenceon metal structures.
PublicationA new detection method has been presented of stray current field interference on underground metal structures. The method employs short time Fourier transformation (STFT). This method of analysis allows determination of signal spectral power density changes (e.g., structure potential) in the function of time. In the paper results have been presented of total time–frequency analysis of a pipeline potential in a stray current field...
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DEIS assessment of AISI 304 stainless steel dissolution process in conditions of intergranular corrosion
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Electrochemical investigations of conductive coatings applied as anodes in cathodic protection of reinforced concrete
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Application of the dynamic EIS to investigation of transport within organic coatings
PublicationW pracy przedstawiono wyniki badań nad gwałtownym niszczeniem organicznych powłok ochronnych. Zastosowano technikę Dynamicznej Elektrochemicznej Spektroskopii Impedancyjnej (DEIS). Przez 60 sekund powłoka poliwinylowa poddawana była działaniu chlorku metylenu. W tym czasie rejestrowano chwilowe widma impedancyjne, co pozwoliło na prześledzenie dynamiki procesu degradacji powłoki. Potwierdzono przydatność techniki DEIS w badaniu...
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Effect of environmental temperature variations on protective properties of organic coatings
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Instantaneous impedance monitoring of synergistic effect between cavitation erosion and corrosion processes
PublicationThe most common method of determination of cavitation erosion resistance as well as the magnitude of erosion-corrosion synergistic interaction is based on the weight loss measurements. Nondestructive characterization of installations elements is in most cases impossible to perform. Also, such a measurement does not include local types of failure or alteration of operating conditions. There is an urge to elaborate a method for monitoring...
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Pitting corrosion in steel and electrochemical noise intensity
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Improved surface coverage of an optical fibre with nanocrystalline diamond by the application of dip-coating seeding
PublicationGrowth processes of diamond thin films on the fused silica optical fibres (10 cm in length) were investigated at various temperatures. Fused silica pre-treatment by dip-coating in a dispersion consisting of detonation nanodiamond (DND) in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) was applied. Nanocrystalline diamond (NCD) films were deposited on the fibres using the microwave plasma assisted chemical vapour deposition...
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Impedance of metastable pitting corrosion
PublicationPrzeprowadzono badania impedancyjne metastabilnego procesu korozji wżerowej. Kształt chwilowych widm impedancyjnych otrzymanych w wyniku eksperymentu jest ściśle związany z przebiegiem prądu dc. O szybkość korozji wewnątrz aktywnego zaatakowania decyduje proces przeniesienia ładunku. Ekspansja aktywnej powierzchni jest proporcjonalna do zmian podwójnej warstwy elektrycznej. Zaobserwowane zostały również zmiany rezystancji elektrolitu...
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Heterogeneous oxidation of highly boron-doped diamond electrodes and its influence on the surface distribution of electrochemical activity
PublicationThe electrochemical active surface area (EASA) of polycrystalline boron-doped diamond (BDD) electrodes is heterogeneous and can be affected by numerous factors. There is a strong need for proper consideration of BDD heterogeneity in order to improve this material's range of application in electrochemistry. Localized changes in surface termination due to the influence of oxidation agent result in increased surface resistance. The...
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Assessment of organic coating degradation via local impedance imaging
PublicationThe paper presents a new approach to organic coating condition evaluation at micrometer scale using localized impedance measurements. It is based on atomic force microscopy (AFM) in contact mode. Impedance is measured between conductive AFM tip and metal substrate covered with organic coating. A single-frequency voltage perturbation signal is applied between the electrodes and current response signal is registered. As the tip is...
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Impedance Measurement and Selection of Electrochemical Equivalent Circuit of a Working PEM Fuel Cell Cathode
PublicationThe dynamic impedance analysis of direct methanolfuel cell (DMFC) cathode supplied with pure oxygen is pre-sented. Presented results were obtained during dynamic chang-es of the current density in working fuel cell. Investigation ofthe occurring processes at cathode was carried with dynamicelectrochemical impedance spectroscopy (DEIS). A discussionwas conducted based on the determined correlation parameterχ2. It was shown that...
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Linearization in impedance measurements
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Ellipsometric investigation of nitrogen doped diamond thin films grown in microwave CH4/H2/N2 plasma enhanced chemical vapor deposition
PublicationThe influence of N2 concentration (1%–8%) in CH4/H2/N2 plasma on structure and optical properties of nitrogen doped diamond (NDD) films was investigated. Thickness, roughness, and optical properties of the NDD films in the VIS–NIR range were investigated on the silicon substrates using spectroscopic ellipsometry. The samples exhibited relatively high refractive index (2.6 6 0.25 at 550 nm) and extinction coefficient (0.05 6 0.02...
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Dynamic Electrochemical Impedance Spectroscopy (DEIS) as a Tool for Analyzing Surface Oxidation Processes on Boron-Doped Diamond Electrodes
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Amperometric sensing of chemical oxygen demand at glassy carbon and silicon electrodes modified with boron-doped diamond
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Electrical mapping of AISI 304 stainless steel subjected to intergranular corrosion performed by means of AFM-LIS in the contact mode
PublicationThe paper presents results of the AFM-based approach to local impedance spectroscopy (LIS) measurements performed in a 20 20 lm grid within an austenite grain–grain boundary region for sensitized AISI 304 stainless steel (SS). Maps of electrical parameters obtained on the basis of localized impedance spectra were demonstrated, presenting their changes and correlation with the sample topography. Performed research revealed significant...
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DEIS evaluation of the relative effective surface area of AISI 304 stainless steel dissolution process in conditions of intergranular corrosion
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Determination of pitting corrosion stage of stainless steel by galvanodynamic impedance spectroscopy
PublicationThis paper investigates the methodology for differentiation of multistep process of pitting corrosion of AISI 304 stainless steel in the environment of iron (III) chloride. Measurements were performed using Galvanodynamic Electrochemical Impedance Spectroscopy (GDEIS). Application of this methodology allowed monitoring of natural corrosion process without external current (IDC = 0A) nor potential perturbation of the system. Applied...
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Ellipsometric study of oxide formation on Cu electrode in 0.1 M NaOH
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Nonlinearity of electrochemical noise caused by pitting corrosion
PublicationPomiary wielkości statystycznych, innych niż rozkład widmowy czy amplitudowy mogą być źródłem dodatkowych informacji na temat mechanizmu powstawania szumu elektrochemicznego. Bispektrum stosowane jest do wykrycia istnienia składowych nieliniowych w badanym rejestrze szumowym. Analizowano elektrochemiczny szum prądowy rejestrowany w warunkach korozji wżerowej. Zaobserwowano zależność prąd-czas charakterystyczną dla stanu tworzenia...
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The time dependence of pit creation impedance spectra
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Electrochemically Induced Synthesis of Triphenylamine-based Polyhydrazones
PublicationTriphenylamine-based hydrazones were subjected to electropolymerization process that gave well conductive hydrazone based polymers. The first example of polyhydrazone formation during the electrochemical process was shown. The estimation of polymer structure was demonstrated using IR spectroelectrochemistry. The EPR spectroelectrochemistry allowed to explain why in some cases dimer couldn’t be formed. The results of electrochemical,...
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Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks
PublicationDynamic Electrochemical Impedance Spectroscopy (DEIS) was presented as novel method for diagnostic and monitoring of PEMFC stack and single cells operation. Impedance characteristics were obtained simultaneously with current - voltage characteristics for stack and each individual cell. Impedance measurements were performed in galvanodynamic mode. It allowed to compare performance of each cell and identification of faulty cell operation...
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Electrochemical characterization of Prussian blue type nickel hexacyanoferrate redox mediator for potential application as charge relay in dye-sensitized solar cells
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Simultaneous impedance and volumetric studies and additionally potentiodynamic polarization measurements of molasses as a carbon steel corrosion inhibitor in 1M hydrochloric acid solution
PublicationThe inhibition effect of molasses on the corrosion of low carbon steel in 1M hydrochloric acid solution was investigated by volumetric and electrochemical measurements. Potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (DEIS) results were obtained and compared with to those, obtained with the hydrogen evolution technique. All results indicate that molasses functioned as a good inhibitor in 1M hydrochloric...
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Detection of random transients caused by pitting corrosion
PublicationProces korozyjny może być badany za pomocą techniki szumu elektrochemicznego. Szum obserwowany jest jako fluktuacje prądowe i napięciowe w trójelektrodowym układzie pomiarowym. W celu stwierdzenia obecności korozji wżerowej wykonana została detekcja charakterystycznych sygnałów. Opracowany został algorytm oparty na analizie lokalnych zmian w spektrogramie rejestru prądowego. Spektrogram uzyskany został za pomocą krótkoczasowej...
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Study of anticorrosion and microwave absorption properties of NiZn ferrite pigments
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