No (543)
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543
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Material design problems of plasma-chemical reactors for disposal perfluorinated compounds
Brožek, Vlastimil; Březina, Václav; Mastný, L.; Kubatík, Tomáš František; Živný, Oldřich
2017 - English
Reduction of perfluorinated gases emissions from semiconductor industry has recently introduced a serious problem from both technological and economic side. With respect to chemistry of the decomposition reactions the most effective abatement techniques developed up to now consists in the interaction of those gaseous pollutants with several types of plasmas. In the framework of Czech-Taiwanese bilateral project No. 17-10246J 'Decomposition of Perfluorinated Compounds and Fluorinated Ozone Depleting Substances' a new plasmochemical reactor design is to be solved. In this reactor the plasma abatement process consisting of interaction of the plasma generated by unique watter stabilized H-WSP plasma torch at temperatures ranging\nfrom 2000 K up to 25,000 K with the treated gases will be carried out. However, the main product generated in the reactor during the steam plasma abatement process is hydrogen fluoride which causes corrosion of almost every construction material. The aim pursued by the work presented is to search for the materials resistant to exposition of HF even at high temperatures. To investigate corrosion resistance of construction materials with thermal stability within temperature interval 2700-3000 °C titan nitride, boron nitride, and silicon carbide have been selected. The samples of those materials have been prepared by spark plasma sintering method and exposed to concentrated solution of hydrofluoric acid for which corrosion rates have been measured
Keywords:
perfluorinated compounds; thermal plasma torch; boron nitride; titanium nitride; silicon carbide
Available at various institutes of the ASCR
Material design problems of plasma-chemical reactors for disposal perfluorinated compounds
Reduction of perfluorinated gases emissions from semiconductor industry has recently introduced a serious problem from both technological and economic side. With respect to chemistry of the ...
ADHESION OF BIOCOMPATIBLE TiNb COATING
Kolegar, T.; Matoušek, M.; Vilémová, Monika; Starý, V.
2017 - English
Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several materials such as titanium CP grade 2, titanium alloys Ti6Al4V and stainless steel AISI 316L were measured. Testing samples were made in the shape of small discs. Those samples were coated with a TiNb layer by using the PVD method (magnetron sputtering). Onto the measured layer of TiNb an assistant cylinder was stuck using a high strength epoxy adhesive E1100S. The sample with the assistant cylinder was fixed into a special fixture and the whole assembly underwent pull-off testing for adhesion. The main result of this experiment was determining the strength needed to peel the layer and morphology and size of the breakaway. As a result, we will be able to determine the best base material and conditions where the coating will be remain intact with the base material.
Keywords:
PVD coating; Adhesion; Biocompatible materials; Pull-off test; Titanium; Niobium
Available at various institutes of the ASCR
ADHESION OF BIOCOMPATIBLE TiNb COATING
Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several ...
Investigation of nanosecond pulsed corona-like discharge generated in deionized water.
Pongrác, Branislav; Šimek, Milan; Babický, Václav; Člupek, Martin; Lukeš, Petr
2017 - English
We employed techniques of time–resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water.
Keywords:
Underwater discharge; nanosecond pulsed discharge; time-resolved emission spectroscopy; time-resolved ICCD imaging
Available at various institutes of the ASCR
Investigation of nanosecond pulsed corona-like discharge generated in deionized water.
We employed techniques of time–resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water.
FÁZOVÁ STABILITA Y2O3 A W-Y2O3 ZPRACOVANÝCH METODOU MECHANICKÉHO LEGOVÁNÍ.
Illková, Ksenia; Vilémová, Monika; Lukáč, František
2017 - Czech
Kinetika fázových transformací B -> C jak v samotném Y2O3 tak i ve slitině W-xY2O3 je velmi důležitá vzhledem k použití těchto materiálů ve vysokoteplotních aplikacích. Chování vysokotlaké fáze B práškového Y2O3 indukované mletím a vlastnosti kompozitu W-Y2O3 byly studovány pomocí diferenční termální analýzy a rentgenové difrakce. Bylo zjištěno, že fázová stabilita je výrazně závislá na rychlosti ohřevu a na době setrvání na dané teplotě. Properties of milling-induced high-pressure B phase in Y2O3 and W-Y2O3 powders were studied by differential thermal analysis and X-Ray diffraction. It was found that phase stability strongly depends on the heating rate and holding time.
Keywords:
yttrium oxide; tungsten; milling; differential thermal analysis
Available at various institutes of the ASCR
FÁZOVÁ STABILITA Y2O3 A W-Y2O3 ZPRACOVANÝCH METODOU MECHANICKÉHO LEGOVÁNÍ.
Kinetika fázových transformací B -> C jak v samotném Y2O3 tak i ve slitině W-xY2O3 je velmi důležitá vzhledem k použití těchto materiálů ve vysokoteplotních aplikacích. Chování vysokotlaké fáze B ...
Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
Ondáč, Peter; Mašláni, Alan; Hrabovský, Milan
2017 - English
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed camera, a high-voltage probe, and a hybrid water–argon plasma torch. The measurements were made for various values of ambient pressure, arc electric current, and argon flow rate. The measured plasma conductivity is in agreement with a model, camera observations and indirectly also with spectroscopy measurements. The procedure provides missing experimental data on the average plasma electrical conductivity and estimates average plasma temperature in the anode areas. The procedure can be theoretically used in every plasma torch where the anode arc attachment movement can be observed during a restrike process\n
Keywords:
DC arc plasma torch; Plasma electrical conductivity; Anode area
Available at various institutes of the ASCR
Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed ...
The role of microstructure on wettability of plasma sprayed yttria stabilized zirconia coatings
Komarov, P.; Čelko, L.; Remešová, M.; Skorokhod, K.; Jech, D.; Klakurková, L.; Slámečka, K.; Mušálek, Radek
2017 - English
Atmospheric plasma spraying utilizing initial powder materials in micrometric size has been successfully used for various applications in different fields of the industry over the past several decades. Nowadays, the new trend in plasma spraying is to use sub-micron or nano-sized powder feedstocks in the form of colloidal suspension. This relatively new technology enables to obtain specific types of dense vertically cracked, fully dense or columnar microstructure. The aim of this work is to investigate the influence of coatings microstructure and topography on its water wetting properties. Two different microstructures, i.e. lamellar and columnar, were sprayed from chemically the same yttria-stabillized zirconia (YSZ) ceramics powders by the means of conventional atmospheric plasma spray and suspension hybrid water stabilized plasma spray techniques, respectively. Microstructural and phase composition of the initial powders and as-sprayed coatings were investigated using optical microscopy, scanning electron microscopy and X-ray diffraction techniques. Topography of coatings surface was measured by means of non-contact optical profilometry. The YSZ coatings wettability was evaluated based on water droplet contact angle using Sessile droplet method. The coatings microstructure reveals the important role in the change of droplet contact angle, where lamellar microstructure was found close to hydrophilic-hydrophobic transition and columnar microstructure was found superhydrophobic
Keywords:
Contact angle; Plasma spraying; Sessile drop method; Water; Yttria stabilized zirconia
Available at various institutes of the ASCR
The role of microstructure on wettability of plasma sprayed yttria stabilized zirconia coatings
Atmospheric plasma spraying utilizing initial powder materials in micrometric size has been successfully used for various applications in different fields of the industry over the past several ...
Vývoj řešení optického řešení Prototypu I
Pintr, Pavel
2017 - Czech
V této práci byly zkoumány jednak možnosti klasického leštění nikl-fosforové (NiP) vrstvy pomocí diamantových leštících suspenzí, dále pomocí Ceroxu jakožto standartního optického leštiva a v neposlední řadě možnosti využití CNC subaperturního leštění pro dosažení optickými aplikacemi vyžadované mikrodrsnosti resp. pro potlačení periodických povrchových struktur vznikajících při procesech opracování pomocí technologie Single Point Diamond Turning. This report describes a development of optical solution for the Prototype I. There is a development of laser collimator in the firt part of this report. You can find a development of freeform optics in the second part of this report.
Keywords:
freeform; laser head; mirror; NIR
Available at various institutes of the ASCR
Vývoj řešení optického řešení Prototypu I
V této práci byly zkoumány jednak možnosti klasického leštění nikl-fosforové (NiP) vrstvy pomocí diamantových leštících suspenzí, dále pomocí Ceroxu jakožto standartního optického leštiva a v ...
Optimalizace procesu výroby optických komponent
Doleček, Roman; Pintr, Pavel
2017 - Czech
Zpráva popisuje vývoj řešení optimalizace procesu výroby freeform zrcadel, které jsou částí optické soustavy pro Prototyp I. This report describes a development of the optimization of the freeform mirror production process. Mirrors are part of optical system of the Prototype I.
Keywords:
freeform mirror; SPDT; laser head
Available at various institutes of the ASCR
Optimalizace procesu výroby optických komponent
Zpráva popisuje vývoj řešení optimalizace procesu výroby freeform zrcadel, které jsou částí optické soustavy pro Prototyp I....
Aspheric lenses test report
Lédl, Vít; Melich, Radek; Procháska, František; Steiger, Lukáš; Chiarini, M.; Cibin, L.
2017 - English
The scope of the document is to report the results of the tests on each of the 16 Aspheric Lenses + the 4 spare Aspheric Lens. \nIn particular, the tests performed on each lens are: reflectance of the coating on both the Aspheric Lens faces, interferometric profile of the Aspherical face and of the Spherical face of the Aspherical Lens.
Keywords:
aspherical lens; coating; interferometry
Available at various institutes of the ASCR
Aspheric lenses test report
The scope of the document is to report the results of the tests on each of the 16 Aspheric Lenses + the 4 spare Aspheric Lens. \nIn particular, the tests performed on each lens are: reflectance of the ...
Nanosecond discharge in deionized water: morphology, propagation velocity and optical emission during initial phase.
Šimek, Milan; Pongrác, Branislav; Babický, Václav; Člupek, Martin; Lukeš, Petr
2017 - English
In this work, we have explored micro-discharges produced in deionized liquid water by applying fast-rising positive HV pulses of nanosecond duration (pulses of ~80 kV in amplitude and of 5 ns in duration, either with the repetition rate of 1 Hz or in a single-shot regime) in a point-to-plane electrode geometry.
Keywords:
Underwater discharge; nanosecond pulsed discharge; time-resolved emission spectroscopy; time-resolved ICCD imaging
Available at various institutes of the ASCR
Nanosecond discharge in deionized water: morphology, propagation velocity and optical emission during initial phase.
In this work, we have explored micro-discharges produced in deionized liquid water by applying fast-rising positive HV pulses of nanosecond duration (pulses of ~80 kV in amplitude and of 5 ns in ...
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