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Printed insulating interlayrs
Olejníková, Marie ; Zmeškal, Oldřich (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with preparation and study of printed insulating interlayers based on barium titanate. The composition of ink formulation and method of deposition were investigated. The composition was optimised with the type of added binder. The printing was made using a screen printing method. Characterisation of prepared layers was made using contact profilometry and optical microscopy. Dielectric properties of layers were subsequently analysed using the impedance spektroskopy method.
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Dielectric layers fabricated by material printing
Olejníková, Marie ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This master‘s thesis deals with the use of the material printing method for fabrication of dielectric films. Final high- dielectric composite film consisted of BaTiO3 based inkjet-printed layer and spin-coated polyvinylpyrrolidone (PVP) layer. The effect of ball-milling on BaTiO3 suspension was studied by DLS a XRD methods. Printing formulation and parameters of inkjet printing were optimized with respect to the surface morphology of printed BaTiO3 films using contact profilometry method. Impedance analysis was used to determine the value of effective dielectric constant of the final dielectric composite film using thin film capacitor structure. Effective dielectric constant of composite dielectric film was 4,9 ± 0,4.
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Study of ferroelectric materials
Kos, Lukáš ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work is focused on the study of perovskite ferroelectric materials group and monitoring changes their dielectric parameters in temperature and frequency dependence Is described scrystallographic systems of barium titanate and their influence on material properties. The measured values are mathematically interpreted using the Curie – Weiss law and discussed about the influence of strontium titanite on important dielectric parameters.
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Electrospinning of composite fiberous structures for piezoapplications
Schifferová, Zuzana ; Kaštyl, Jaroslav (referee) ; Částková, Klára (advisor)
Polymer and composite polymer-ceramic nanofibers were prepared by electrospinning process. Solution of 20 wt.% polyvinylidene fluoride (PVDF) in a mixture of dimethyl sulfoxide (DMSO) and acetone in the ratio of 7:3 was chosen as the most suitable precursor. When preparing composite nanofibers, 20 wt.% of barium calcium zirconate titanate (BCZT) or barium titanate (BT) nanoparticles was added to this PVDF solution. Given parameters were defined as the most suitable for the process of electrospinning: voltage of 50 kV, feeding rate of 30 l/min, distance between emitter and collector of 20 cm and needle diameter of 17 G. The effect of polymer molecular weight and the rotation speed of collector was also studied. Various properties of prepared samples were studied: morphology and fiber diameter, phase composition with the use of x-ray diffraction and Fourier transform infrared spectroscopy and also chosen electrical properties. Lower fiber diameters appeared with lower polymer molecular weight and higher rotation speed of the collector. These parameters resulted in higher percentage of the piezoelectric phase as well. The smallest achieved fiber diameter was around 300 nm, the highest percentage of phase was 92 % and the highest piezoelectric constant had a value of 16 pC/N. Composite fibers filled with BT particles showed better properties that the ones filled with BCZT particles.
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Dielectric layers fabricated by material printing
Olejníková, Marie ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This master‘s thesis deals with the use of the material printing method for fabrication of dielectric films. Final high- dielectric composite film consisted of BaTiO3 based inkjet-printed layer and spin-coated polyvinylpyrrolidone (PVP) layer. The effect of ball-milling on BaTiO3 suspension was studied by DLS a XRD methods. Printing formulation and parameters of inkjet printing were optimized with respect to the surface morphology of printed BaTiO3 films using contact profilometry method. Impedance analysis was used to determine the value of effective dielectric constant of the final dielectric composite film using thin film capacitor structure. Effective dielectric constant of composite dielectric film was 4,9 ± 0,4.
|
|
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Printed insulating interlayrs
Olejníková, Marie ; Zmeškal, Oldřich (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with preparation and study of printed insulating interlayers based on barium titanate. The composition of ink formulation and method of deposition were investigated. The composition was optimised with the type of added binder. The printing was made using a screen printing method. Characterisation of prepared layers was made using contact profilometry and optical microscopy. Dielectric properties of layers were subsequently analysed using the impedance spektroskopy method.
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|
|
Electrospinning of composite fiberous structures for piezoapplications
Schifferová, Zuzana ; Kaštyl, Jaroslav (referee) ; Částková, Klára (advisor)
Polymer and composite polymer-ceramic nanofibers were prepared by electrospinning process. Solution of 20 wt.% polyvinylidene fluoride (PVDF) in a mixture of dimethyl sulfoxide (DMSO) and acetone in the ratio of 7:3 was chosen as the most suitable precursor. When preparing composite nanofibers, 20 wt.% of barium calcium zirconate titanate (BCZT) or barium titanate (BT) nanoparticles was added to this PVDF solution. Given parameters were defined as the most suitable for the process of electrospinning: voltage of 50 kV, feeding rate of 30 l/min, distance between emitter and collector of 20 cm and needle diameter of 17 G. The effect of polymer molecular weight and the rotation speed of collector was also studied. Various properties of prepared samples were studied: morphology and fiber diameter, phase composition with the use of x-ray diffraction and Fourier transform infrared spectroscopy and also chosen electrical properties. Lower fiber diameters appeared with lower polymer molecular weight and higher rotation speed of the collector. These parameters resulted in higher percentage of the piezoelectric phase as well. The smallest achieved fiber diameter was around 300 nm, the highest percentage of phase was 92 % and the highest piezoelectric constant had a value of 16 pC/N. Composite fibers filled with BT particles showed better properties that the ones filled with BCZT particles.
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|
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Study of ferroelectric materials
Kos, Lukáš ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work is focused on the study of perovskite ferroelectric materials group and monitoring changes their dielectric parameters in temperature and frequency dependence Is described scrystallographic systems of barium titanate and their influence on material properties. The measured values are mathematically interpreted using the Curie – Weiss law and discussed about the influence of strontium titanite on important dielectric parameters.
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