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Surface acoustic waves in the layered systems
Tarasenko, Alexander ; Boháč, Petr ; Jastrabík, Lubomír
The laser acoustic method was used for analysis of two layered systems: thin titanium and diamond like carbon films both deposited on silicon. The film and substrate parameters are determined by fitting the theoretical curve to the measured dispersion curve. The fit software seeks that set of the system parameters whose theoretical curve coincides the best with the experimental data. For the titanium film the best root-mean square deviation was 2.04 m/s with the relative error < O.I % and for the DLC system the corresponding value was 0.30 m/s (the relative error < O.O1 % ).
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Application of acoustic emisssion for thin layer mechanical toughness evaluation
Boháč, Petr ; Tomáštík, Jan ; Koula, V. ; Dráb, M. ; Jastrabík, Lubomír
The thin films are used as a functional coating of components. The limiting factor of their application is the adhesion to substrate. The laboratory method to investigation of their adhesion and mechanical toughness is the scratch test. This method emulates a mechanism of the abrasive wear in a way. Evaluation of the test results is mainly performed by microscopic investigation of deformations and micro cracks in the scratch track. Irreversible deformations, which arise during scratch test generate an acoustic emission (AE). By simultaneous scanning and recording of the increasing depth of penetration with increasing load of the stylus in the nanotester and by this way generated AE (recorded by analyzer)one can obtain data files, which contain a course of the whole experiment including AE.
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Photo-Electrochemical Properties of Hierarchical Nanocomposite Structure: Carbon Nanofibers/TiO2/ZnO Thin Films
Hubička, Zdeněk ; Kment, Štěpán ; Gregora, Ivan ; Čada, Martin ; Olejníček, Jiří ; Klusoň, Petr ; Petras, D. ; Krýsa, J. ; Jastrabík, Lubomír ; Dytrych, Pavel
In this contribution we report on photoelectrochemical functionality of the multilayers system consisting of CNF's/photoactive anatase TiO2/ conductive ZnO thin films. Recently the thin phthalocyanines films has been prepared and studied individually.
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Depozice tenkých vrstev Ba.sub.x./sub.Sr.sub.1-x./sub.TiO.sub.3./sub. pomocí dvoutryskového RF plazmatického systému s efektem duté katody
Hubička, Zdeněk ; Virostko, Petr ; Olejníček, Jiří ; Deyneka, Alexander ; Adámek, Petr ; Valvoda, V. ; Jastrabík, Lubomír ; Šícha, Miloš ; Tichý, M.
Low-pressure plasma jet system with two hollow cathodes was used for deposition of BaxSr1-xTiO3 (BSTO) ferroelectric thin films. High density pulse modulated RF hollow cathode discharge was generated in ceramic nozzles made of SrTiO3 and BaTiO3. In the experiment, the composition of BSTO films was controlled by magnitude of average RF power applied on particular plasma jet guns. X-ray diffraction proved that BSTO thin films were polycrystalline with perovskite structure. Time resolved Langmuir probe system and plasma impedance monitor were used for ´in situ´ plasma diagnostics and control of deposition conditions.
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Měření tvrdosti nehomogenních plazmových nástřiků
Čtvrtlík, Radim ; Stranyánek, Martin ; Boháč, Petr ; Jastrabík, Lubomír ; Hrabovský, Milan ; Ctibor, Pavel
Paper deals with testing of mechanical properties of plasma sprayed coatings TiO2 by Depth Sensing Indentation performed on measuring system NanoTest 600™. The NT600™ is a modular measuring instrument with unique design, which applies the loading force in horizontal direction. The platform can measure and evaluate hardness, elastic modulus, adhesion, wear, fracture and also dynamic properties. In the last years the new plasma spraying technology of ceramic and ceramic-metal materials has became as very convenient technique in many industrial and reconstruction processes. The investigated samples of plasma sprayed coatings were prepared in Institute of Plasma Physics of the Academy of Sciences of the Czech Republic. The goal of this paper is to contribute to deepening the knowledge in local distribution of mechanical properties in plasma sprayed coatings, especially of hardness and elastic modulus.
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