Number of found documents: 599
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Composite coatings containing nanometric constituents prepared by plasma spraying with liquid feedstocks
Mušálek, Radek; Tesař, Tomáš; Medřický, Jan; Čížek, Jan; Lukáč, František
2022 - English
Plasma spraying of liquid feedstocks allows deposition of materials with novel microstructures. Due to the combination of a liquid carrier and ultrafine powders (in case of suspensions) or in-situ formation of the final material in the plasma jet (in case of solutions), preparation of ultrafine composites is possible, typically in a form of coatings on the substrates. Moreover, both suspension and solution spraying routes can be easily combined, either together or even with conventional plasma spraying of coarse dry powders, thus merging benefits of “nanometric” and “micrometric” constituents in the final composite microstructure. As a consequence, liquid feedstock plasma spraying represents an industrially-relevant deposition process with wide variability, providing coatings with properties tailored for various applications ranging from compact wear-resistant layers, porous thermal barrier coatings, bio-compatible medical coatings, catalyst carriers, fuel-cells, etc. The paper introduces several examples of such ultrafine coatings recently deposited at IPP CAS using hybrid water-stabilized plasma torch. Keywords: Coatings; Functionally graded materials (FGMs); Liquid feedstock; Plasma spraying Fulltext is available at external website.
Composite coatings containing nanometric constituents prepared by plasma spraying with liquid feedstocks

Plasma spraying of liquid feedstocks allows deposition of materials with novel microstructures. Due to the combination of a liquid carrier and ultrafine powders (in case of suspensions) or in-situ ...

Mušálek, Radek; Tesař, Tomáš; Medřický, Jan; Čížek, Jan; Lukáč, František
Ústav fyziky plazmatu, 2022

High temperature corrosion behaviour of nicr-based coatings applied by twin wire arc spray technology
Lencová, K.; Vostřák, M.; Naďová, J.; Lukáč, František; Mušálek, Radek
2021 - English
High temperature corrosion is a serious problem related to the combustion of heavy oils with high vanadium contents. Protective overlay coatings are used to allow functioning of engineering components under extreme conditions and provide corrosion resistance to extend the component life. This article is concerned with the high temperature corrosion behaviour of two protective NiCr-based coatings and bare structural steel 1.4959 (W.nr.) in a molten salt environment of 40% Na2SO4 and 60% V2O5 at 750 °C under cyclic condition. NiCr and NiCrMoNbTa coating was deposited on steel 1.4903 (W.nr.) by Twin wire arc spray technology (TWAS). To establish the kinetics of corrosion, the thermogravimetric technique was used. The X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) techniques were used to analyse the corrosion products and determine the corrosion mechanism. The hot corrosion resistance of both coatings was better than bare steel samples. The NiCrMoNbTa coating showed better corrosion behaviour than the NiCr coating. However, also the NiCr coating provides sufficient protection to the substrate material. Keywords: Heavy oils; High temperature corrosion; NiCr; NiCr-based coating; NiCrMoNbTa; Twin Wire Arc Spray; Vanadium Available at various institutes of the ASCR
High temperature corrosion behaviour of nicr-based coatings applied by twin wire arc spray technology

High temperature corrosion is a serious problem related to the combustion of heavy oils with high vanadium contents. Protective overlay coatings are used to allow functioning of engineering components ...

Lencová, K.; Vostřák, M.; Naďová, J.; Lukáč, František; Mušálek, Radek
Ústav fyziky plazmatu, 2021

Metodika charakterizace tvaru laserových tyčí pomocí multi vlnové interferometrie
Matoušek, Ondřej; Kredba, Jan; Procháska, František
2020 - Czech
Vytvořená metodika popisuje metodu multi vlnové interferometrie s řízenou změnou fáze a způsob její aplikace pro charakterizaci laserových tyčí, která umožňuje měření tvaru čelních povrchů, klínu, deformace průchozí vlnoplochy a vnitřní nehomogenity v jediném měřícím cyklu. The developed methodology describes the method of the multi-wave interferometry with controlled phase changing and the way of its application for the characterization of laser rod, which allows measurement of the shape of the front surfaces, wedge, deformation of the passing wavefront and internal inhomogeneity in a single measuring cycle Keywords: Multi-wave interferometry Available at various institutes of the ASCR
Metodika charakterizace tvaru laserových tyčí pomocí multi vlnové interferometrie

Vytvořená metodika popisuje metodu multi vlnové interferometrie s řízenou změnou fáze a způsob její aplikace pro charakterizaci laserových tyčí, která umožňuje měření tvaru čelních povrchů, klínu, ...

Matoušek, Ondřej; Kredba, Jan; Procháska, František
Ústav fyziky plazmatu, 2020

Microstructure and microhardness evaluation for NiCrAlY materials manufactured by spark plasma sintering and plasma spraying
Hulka, Iosif; Mušálek, Radek; Lukáč, František; Klečka, Jakub; Chráska, Tomáš
2020 - English
NiCrAlY deposited by different thermal spraying methods is commonly used as the bond coat material in thermal barrier coatings (TBCs). In the present study, two experimental coatings were deposited by hybrid water stabilized plasma (WSP-H) and radio frequency inductively coupled plasma (RF-ICP) using the same feedstock powder. Spark plasma sintering (SPS) was used to manufacture a compact NiCrAlY from the same feedstock powder as a reference material. Microstructure, internal oxidation, phase characterization and quantification of the mechanical behaviour in terms of microhardness were studied. The investigations clearly showed microstructural and mechanical differences between the NiCrAlY samples manufactured by different plasma technologies. The results confirmed that SPS and RF-ICP provide dense structures with no oxides due to the fabrication under protective atmosphere and similar mechanical properties. Thus, RF-ICP may be used for deposition of very dense coatings with microstructure and hardness comparable to compacted materials prepared by SPS. Keywords: Microhardness; Microstructure; NiCrAlY; Plasma spraying; Spark plasma sintering Available at various institutes of the ASCR
Microstructure and microhardness evaluation for NiCrAlY materials manufactured by spark plasma sintering and plasma spraying

NiCrAlY deposited by different thermal spraying methods is commonly used as the bond coat material in thermal barrier coatings (TBCs). In the present study, two experimental coatings were deposited by ...

Hulka, Iosif; Mušálek, Radek; Lukáč, František; Klečka, Jakub; Chráska, Tomáš
Ústav fyziky plazmatu, 2020

Tungsten-steel and tungsten-chromium composites prepared by RF plasma spraying
Matějíček, Jiří; Klečka, Jakub; Čížek, Jan; Veverka, Jakub; Vilémová, Monika; Chráska, Tomáš; Ganesh, V.
2020 - English
For future fusion reactors, materials able to withstand harsh environments are needed. In particular, this concerns the plasma-facing components which are foreseen to consist of tungsten based plasma-facing armor and structural and cooling part made of steel. Currently, joining of these materials presents a significant challenge. The stress concentration at their interface, which arises due to thermal exposure and the difference in thermal and mechanical properties, can be reduced by composite/graded interlayers. Plasma spraying is among the prospective technologies for their preparation. In this work, tungsten-steel and tungsten-chromium composites were prepared by radio-frequency inductively coupled plasma (RF-ICP) spraying. Initial optimization of the spraying process for pure materials as well as their mixtures was carried out. Basic characterization of the layers for their structure, porosity and composition is presented. Keywords: tungsten; composites; RF plasma spraying Fulltext is available at external website.
Tungsten-steel and tungsten-chromium composites prepared by RF plasma spraying

For future fusion reactors, materials able to withstand harsh environments are needed. In particular, this concerns the plasma-facing components which are foreseen to consist of tungsten based ...

Matějíček, Jiří; Klečka, Jakub; Čížek, Jan; Veverka, Jakub; Vilémová, Monika; Chráska, Tomáš; Ganesh, V.
Ústav fyziky plazmatu, 2020

Bakerova širokoúhlá fotografická komora s paraboloidickým zrcadlem
Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Vápenka, David; Tomka, David; Thoř, Tomáš; Pintr, Pavel; Macner, David
2020 - Czech
Zorné pole paraboloidického zrcadla je malé. Dominantní vada, která omezuje jeho úhlový průměr, je koma. Pomocí systémů čoček a asférických desek je možné u zrcadlových systémů mimoosové obrazy hvězd opravit a zorná pole zvětšit. V této práci předkládáme návrh takové fotografické komory, spočtené Jamesem G. Bakerem. Jeho fotografický přístroj se skládá z paraboloidického zrcadla, tmeleného dubletu před ohniskem a z asférické korekční desky, umístěné ve vstupním paralelním svazku před soustavou. A field of view of the paraboloidal mirror is small. Dominant aberration which limits its angular diameter is coma. Using correctors consisting lenses and aspherical plates star images of the mirror systems can be radically corrected. In this paper we present optical design of such photographic camera computed by James G. Baker. His device is composed of a paraboloidal mirror, a cemented dublet in front of focus and an aspherical plate placed in entrance parallel beam. Keywords: paraboloidal mirror; lens corrector; cemented dublet; aspheric plate; optical aberrations Available at various institutes of the ASCR
Bakerova širokoúhlá fotografická komora s paraboloidickým zrcadlem

Zorné pole paraboloidického zrcadla je malé. Dominantní vada, která omezuje jeho úhlový průměr, je koma. Pomocí systémů čoček a asférických desek je možné u zrcadlových systémů mimoosové obrazy hvězd ...

Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Vápenka, David; Tomka, David; Thoř, Tomáš; Pintr, Pavel; Macner, David
Ústav fyziky plazmatu, 2020

Design of experimental device for testing of subcooled flow boilling
Gleitz, M.; Zacha, P.; Entler, Slavomír; Syblík, J.
2020 - English
The article presents the principle and function of the Hypervapotron and the current work progress on the realisation of the experimental loop. Hypervapotron is a heat exchanger operating in a two-phase flow regime, in which the latent heat of the water/steam phase transformation is used, which enables the transfer of large heat fluxes (up to tens of MW/m(2)). For this reason, it appears to be very promising for use in fusion reactors. The article describes the steps leading to the final design of the experimental loop selection of suitable mesh parameters in the Star-CCM+ code, geometry and used materials of the single elements of the heating system using electromagnetic induction. The effort of the experimental loop and the flow study in the Hypervapotron in general, is dimensional and material optimization of the geometry is suitable for a wide range of applications for which the benefits of subcooled boiling and Hypervapotron geometry can be applied. Keywords: Hypervapotron; Star-CCM; Fusion; Subcooled boiling; Induction heating Fulltext is available at external website.
Design of experimental device for testing of subcooled flow boilling

The article presents the principle and function of the Hypervapotron and the current work progress on the realisation of the experimental loop. Hypervapotron is a heat exchanger operating in a ...

Gleitz, M.; Zacha, P.; Entler, Slavomír; Syblík, J.
Ústav fyziky plazmatu, 2020

Technologie výroby spojky achromatického dubletu
Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Šípová, Gabriela; Ulrichová, Iva; Franců, Helena; Melich, Radek; Vápenka, David; Tomka, David; Thoř, Tomáš
2020 - Czech
Tento referát popisuje technologický postup výroby spojky achromatického dubletu o průměru 158 mm a ohniskové vzdálenosti 2500 mm. Sklo, ze kterého byla vyrobena původní spojka, bylo nehomogenní a dublet špatně zobrazoval. Z tohoto důvodu jsme se rozhodli vyrobit novou spojku. Její výroba byla provedena na původních strojích naší dílny. Dublet je umístěn v dalekohledu na turnovské hvězdárně a slouží k veřejnému pozorování oblohy. This paper deals with manufacturing of a positive lens of achromatic dublet. Diameter of the dublet is 158 mm and its focal length about 2500 mm. The glass material of the former lens was inhomogeneous and the dublet provided bad images. This is why we decided to manufacture new lens. The process was made by means of former machines of our workshop. The telescope with this dublet is placed at the Observatory of Turnov and serves for public astronomical observation. Keywords: achromatic dublet; aplanat; coma; pherochromatic aberration Available at various institutes of the ASCR
Technologie výroby spojky achromatického dubletu

Tento referát popisuje technologický postup výroby spojky achromatického dubletu o průměru 158 mm a ohniskové vzdálenosti 2500 mm. Sklo, ze kterého byla vyrobena původní spojka, bylo nehomogenní a ...

Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Šípová, Gabriela; Ulrichová, Iva; Franců, Helena; Melich, Radek; Vápenka, David; Tomka, David; Thoř, Tomáš
Ústav fyziky plazmatu, 2020

Zbytkové vady Gajduškova objektivu o průměru 200 mm a ohniskové vzdálenosti 3480 mm Hvězdárny a planetária v Hradci Králové
Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Vápenka, David; Tomka, David; Thoř, Tomáš; Macner, David
2020 - Czech
Achromatický dublet o průměru 200 mm a ohniskové vzdálenosti 3480 mm byl vyroben profesorem ing. Vilémem Gajduškem v Ostravě v roce 1954. Dalekohled s tímto objektivem je umístěn na Hvězdárně a planetáriu v Hradci Králové. Objektiv byl v roce 2018 restaurován v Ústavu fyziky plazmatu, v.v.i.-Centru Toptec v Turnově. Čočky byly přeměřeny a z naměřených hodnot jsme vyčíslili jeho zbytkové optické vady. Výsledky simulace přinášíme v této práci. The achromatic dublet of diameter 200 mm and focal length 3480 mm was manufactured by Professor ing. Vilém Gajdušek in Ostrava in 1954. The telescope with this objective is placed at the Observatory and planetarium in Hradec Králové. The objective was restored in the Institute of Plasma Physics, v.v.i.-Centrum Toptec in Turnov. During the process lens was measured and data were used for evaluation of its residual aberrations. We present the results of the measurement in this paper. Keywords: achromatic dublet; aplanat; coma; pherochromatic aberration Available at various institutes of the ASCR
Zbytkové vady Gajduškova objektivu o průměru 200 mm a ohniskové vzdálenosti 3480 mm Hvězdárny a planetária v Hradci Králové

Achromatický dublet o průměru 200 mm a ohniskové vzdálenosti 3480 mm byl vyroben profesorem ing. Vilémem Gajduškem v Ostravě v roce 1954. Dalekohled s tímto objektivem je umístěn na Hvězdárně a ...

Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan; Vápenka, David; Tomka, David; Thoř, Tomáš; Macner, David
Ústav fyziky plazmatu, 2020

Digitalizace Maksutovovy komory 350/840 úpické observatoře
Rail, Zdeněk; Melich, Zbyněk
2019 - Czech
Maksutovova komora o průměru 350 mm a ohniskové vzdálenosti 840 mm byla vyrobena v Turnově počátkem 80. let. Na úpické observatoři sloužila k fotografování oblohy na fotografický film. V současné době jsme byli požádáni o jeji přestavbu na digitální přístroj. Pro komoru bylo nutné navrhnout a vyrobit korekční člen pro narovnání její ohniskové plochy a dále ji vybavit vhodným digitálním fotografickým přístrojem. V této práci přinášíme popis úpravy tohoto přístroje. The Maksutov chamber with a diameter of 350 mm and a focal length of 840 mm was manufactured in Turnov in the early 1980s. At the Úpice Observatory it was used to photograph the sky for photographic film. Currently, we have been asked to convert it to a digital device. It was necessary to design and manufacture a correction element for the chamber to straighten its focal surface and to equip it with a suitable digital camera. In this work we present description of modification of this device. Keywords: Maksutov chamber; focal surface Available at various institutes of the ASCR
Digitalizace Maksutovovy komory 350/840 úpické observatoře

Maksutovova komora o průměru 350 mm a ohniskové vzdálenosti 840 mm byla vyrobena v Turnově počátkem 80. let. Na úpické observatoři sloužila k fotografování oblohy na fotografický film. V současné době ...

Rail, Zdeněk; Melich, Zbyněk
Ústav fyziky plazmatu, 2019

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