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Topografia powierzchni i wybrane własności przewodzące cienkich warstw La1-xSrxCoO3 wytworzonych metodą PLD DOI:10.15199/24.2017.4.4


  W pracy przedstawiono wyniki badań dotyczących mikrostruktury i oporu elektrycznego cienkich warstw La1-xSrxCoO3 wytworzonych metodą ablacji laserowej (PLD - Pulsed Laser Deposition). Cienkie warstwy osadzono na monokrystalicznych podłożach Si oraz MgO o orientacji [001] z wykorzystaniem lasera impulsowego na ciele stałym Nd:YAG. Mikrostrukturę wytworzonych warstw zbadano za pomocą wysokorozdzielczego mikroskopu skaningowego (FEI Nova NanoSEM 450 wyposażonego w detektor EDS EDAX). Przeanalizowano także topografię powierzchni cienkich warstw z wykorzystaniem mikroskopu sił atomowych (Veeco Dimension®Icon™ SPM) oraz dokonano pomiaru chropowatości ich powierzchni za pomocą programu NanoScope Analysis. Analiza taka pozwoliła na zweryfikowanie jakości cienkich warstw La1-xSrxCoO3. W celu określenia przydatności wytworzonych warstw do detekcji gazów zbadano zmiany ich rezystancji w atmosferze NO2 z zastosowaniem wyspecjalizowanego stanowiska pomiarowego wykorzystującego elektrometr Keithley 6517 w warunkach stałego napięcia. Stwierdzone zmniejszenie rezystancji warstwy La0,8Sr0,2CoO3 w atmosferze gazu utleniającego jest charakterystyczne dla półprzewodnika typu p oraz zastosowanego gazu utleniającego, co potwierdza własności sensorowe warstwy. Słowa kluczowe: perowskity, cienkie warstwy gazoczułe, metoda PLD, mikrostruktura.Wprowadzenie. Rozwój technologii oraz nieustanny postęp w przemyśle, skłaniają do ciągłej poprawy i opracowania nowych czujników gazów. Zwiększające się zanieczyszczenie środowiska odpadami oraz szkodliwymi dla zdrowia gazami wymuszają większą świadomość konsumentów. Coraz więcej osób decyduje się na stosowanie w gospodarstwach domowych chociażby prostego czujnika gazów dla własnego bezpieczeństwa. Stwarza to nowe możliwości wprowadzenia na rynek nowych materiałów i alternatywnych metod ich wytwarzania. Obserwuje się wzrost zainteresowania nowymi materiałami, takimi jak m.in. materiały o budowie perow[...]

Characterization of lanthanum lutetium oxide thin films grown by pulsed laser deposition

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Exposure to ionizing can occur in the range of industries, medical institution, educational and research establishments and nuclear fuel cycling facilities. Adequate radiation protection is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy [1]. Due to large number of different applications, there are many alternatives of materials and design for radiation sensors or detectors. To optimize the trade-offs that exist among the requirements, different materials, geometric arrangements and different physical detection techniques are used [2]. A number of efforts were devoted to investigate the influence of radiation on the properties of metal-oxide materials [3÷5]. Metal oxides are interesting for their low-cost and simplicity. Properties of metal oxides materials are directly or indirectly connected to the presence of defects. In particular oxygen vacancies determine the optical, electronic and transport properties of the materials and usually dominate the chemistry of its surface. The promising materials for gamma sensor applications are TiO2, TeO2, NiO, CeO2, In2O3, LaFeO3, LaLuO3 [2, 3, 6, 7]. The gamma detecting oxide materials can be in the form of both: thin or thick films [3]. Only crystallized LaLuO3 exhibits luminescence properties that could be used in detection. There are a wide variety of techniques for deposition of thin films. The examples are thermal evaporation (also known as vacuum vapour deposition), electron-beam evaporation, magnetron sputtering, chemical vapour deposition (CVD) and molecular beam epitaxy (MBE) [8÷10]. Pulsed laser deposition was already used to grow amorphous LaLuO3, mainly as high-K gate dielectrics [11], but barely crystallized LaLuO3 films were grown by this technique. For this reason, in the present work to obtain crystallized LaLuO3 thin films PLD technique was used and the morphology and chemical composition of thin films were investigated. I[...]

Investigation of Ni-base coatings after corrosion test DOI:10.15199/28.2016.4.7


  Inconel 625 and 686 are Ni-Cr-Mo alloys used for its high strength, outstanding corrosion resistance, and excellent fabricability. For this reason, these alloys are typically used as a one of the most important coating material and can be applied to chemical and petrochemical plants, power generation sector, heat exchanger tubing for boilers of waste incinerators. To perform the Ni-base weld overlays, without introducing too much Fe, a new weld technique called Cold Metal Transfer (CMT) was used. This paper presents the mechanisms of high-temperature corrosion, microstructure and chemical composition of boiler elements after the waste incineration form ashes at 650°C from 500 h. Microstructure examinations of the Inconel 625 and Inconel 686 corroded surface were carried out by scanning electron microscopy (SEM) supported by energy dispersive spectroscopy (EDS). The phase compositions of the corroded surfaces were carried out by means of X-ray diffraction. Key words: Inconel 625, Inconel 686, corrosion layer.1. INTRODUCTION Corrosion-resistant Ni-base superalloys like Inconel 625 and Inconel 686 are widely used in several industrial sectors, including petrochemical or power generations, due to their high performance in aggressive environments. The field of their application as the structural materials depends, to a large extent, on the concentrations and the ratios between the contents of their main alloying components, primarily, chromium and molybdenum. Nowadays, Ni-base alloys are typically used to manufacture engineering components, or coatings for protection of cheaper metallic substrates, which should work in extreme conditions including mechanical loads and an aggressive environment at high temperature. Due to the excellent high temperature corrosion resistance and good strength at high temperatures Ni-base alloys can work in aggressive environments [1, 2]. Inconel 625 is a metallic materials, austenitic alloy, showing an extrao[...]

Catalytic behaviours and electrical conduction changes in BaCeO3 ceramics synthesized by sol-gel method

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BaCeO3 (BCO) ceramics and related perovskite type compounds were intensively studied because of their high temperature potential applications (e.g. for fuel cell and electrocatalysis technologies) [1÷3]. They were regarded as very promising candidates as solid electrolytes in electrochemical devices such as solid oxide fuel cells (SOFCs) and gas sensors [4÷6]. These perovskite type structures were highly interesting mainly because of their high ionic conductivity. More recently, we found that BaCeO3 exhibited heterogeneous photocatalytic activities for water splitting [7÷10]. Doped barium cerate materials were also investigated as proton conductors in humidified reducing atmosphere at intermediate temperature: these perovskite type materials were also considered as promising electrolytes for SOFCs [11÷14]. The microstructure and the presence of carbon dioxide in the ambient atmosphere were also considered as potential parameters that could condition the conductivity mechanisms [15]. These oxide materials were also found to present high interest as catalysts for oxidation reaction because of their high capacity of oxygen conduction. Recently solid gas interaction analyses between BCO and methane CH4 in air-CH4 flows were published [16, 17]. However, in our knowledge, the solid gas interactions between BaCeO3 and carbon monoxide CO were never studied. In this work, we first study the conversion of CO in air-CO gas mixtures interacting with barium cerate powder, and then we determine the high temperature electrical conductivity of compacted pellets of barium cerate. We report a new synthesis method allowing preparing BaCeO3 perovskite ceramics at moderate temperature (1100°C). Characterizations are achieved using X-ray diffraction and transmission electron microscopy. The catalytic properties are investigated from analyses of emitted gases from Fourier Transform infrared spectroscopy (FTIR). The electrical properties are studied [...]

Polimerowe, ceramiczne i kompozytowe powłoki osadzane elektroforetycznie poprawiające wybrane właściwości materiałów metalowych DOI:10.15199/24.2016.4.7


  W pracy przedstawiono przykłady wytwarzania różnych powłok polimerowych, ceramicznych i kompozytowych na modelowych materiałach metalowych metodą osadzania elektroforetycznego. W celu uzyskania dobrej jakości powłok dobrano optymalny skład chemiczny roztworów koloidalnych i zawiesin stosowanych do osadzania, wyznaczono ich pH i potencjał elektrokinetyczny dzeta. W oparciu o badania makroskopowe osadzonych powłok dobrano napięcie prądu i czas osadzania elektroforetycznego. Wykonano badania mikrostruktury powłok i ich wybranych właściwości, takich jak odporność na korozję, odporność na zużycie ścierne i wyznaczono współczynnik tarcia. Wykazano, że osadzanie elektroforetyczne jest perspektywiczną metodą wytwarzania powłok: polimerowych (chitozanu i polieteroeteroketonu (PEEK)), ceramicznych (SiO2), kompozytowych (szkło żelowe/chitozan, TiO2/chitozan, SiO2/HA i Ni/SiO2) oraz porowatych (szkło żelowe/PEEK). This work presents the examples of electrophoretic deposition of various polymer, ceramic and composite coatings on model metallic materials. To obtain good quality coatings, chemical composition of colloidal solutions and suspensions as well as their pH and Zeta potential were optimized. The voltage and deposition time were experimentally selected by macroscopic examination of as-deposited coatings. Investigation of the coatings comprised microstructural analysis as well as determination of their corrosion resistance, wear resistance and friction coefficient. It was demonstrated that electrophoretic deposition is a prospective method for obtaining various coatings: polymer chitosan and polyetheroetheroketone (PEEK), ceramic SiO2, composite gel glass/chitosan, TiO2/chitosan, SiO2/HA and Ni/SiO2 as well as porous sol-gel glass/PEEK coatings. Słowa kluczowe: osadzanie elektroforetyczne, powłoki polimerowe, powłoki kompozytowe, mikrostruktura, odporność korozyjna, odporność na zużycie ścierne Key words: electrophoretic deposition, polymer coatin[...]

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