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Preparation of nanoforms of layered piezoelectric of systems BI2O3-TA(2)O(5)-AO (A=CA,SR,BA)
Štarman, S. ; Matz, V. ; Kváča, Z. ; Mohyla, M. ; Olšák, V. ; Plocek, Jiří ; Vaněk, Přemysl ; Tylš, B.
Based on the known Aurivillius phases types ABi2Ta2O9 and A2BiTaO6 ( A=Ca, Sr, Ba) were supplemented with new compositions of layered tantalates, which resulted the possibility of the existence of a new phase Sr2BiTaO6. Ternary compounds with piezoelectric structure were prepared as nanoforms by solgel reactions of homogeneous acetate Bi, Ta, A and subsequent annealing in a controlled atmosphere. Annealing temperature was determined from DSC curves based on the weight loss and phase transitions. Composition and structure of nanocrystals has been analyzed by X-ray diffraction (XRD), scanning nanomorphology (SEM) and acoustic measurements.
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Nonisometric pigments in coating for the corrosion protection of metals
Tamchynová, P. ; Kalendová, A. ; Štengl, Václav ; Kváča, Zdeněk
The paper deals with various types of nonisometric pigments and the effect therof on the protection coating materials properties. New type of lamellar pigments is the surface treated mica-muscovite, which forms the proper core or the layer carrier. At the carrier surface a layer of ferric oxide-hematite is formed. The contribution of these lamellar pigments is evaluated from the adhesion-barrier efficiency point of view or, maybe, the anticorrosion efficiency thereof in coating materials.
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Nanodisperzní oxidy a hydroxidy Mg, Al a Ti
Šubrt, Jan ; Štengl, Václav ; Svobodová, Monika ; Bezdička, Petr ; Kváča, Zdeněk ; Večerníková, Eva ; Bakardjieva, Snejana
Z organických prekursorů a cestou homogenního srážení byly připraveny nanočásticové oxidy a hydroxidy Mg, Al, Ti a Fe. Hydroxidy byly zpracovány metodou sušení nad kritickou teplotou a charakterizovány pomocí elektronové mikroskopie a difrakce, změření specifického povrchu, práškovou rentgenovou difraktometrií a termickou analýzou.
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