Piezoceramics BaTiO3 doped with ZrO2 was studied in this thesis. Six different compositions were prepared from base powders of BaTiO3 and ZrO2. with 10, 20, 40, 60, 80 and 90 wt% ZrO2. These mixtures were sintered using convetional sintering method and by Spark Plasma Sintering. Resuting ceramic compacts were subjected to measuring of density, dielectric constant, permitivity, polarization P-E curves, piezoelekctric faktor, loss factor and dilatometric measurements. From these results can be said that i tis possible to create piezoceramic BaTiO3 doped by ZrO2 with relative density higher than 94 %t.d. and these ceramics can possess piezoelectric properties. Value of highest piezoelectrick factor 33=9 / was achieved with addition of 20 wt% ZrO2. Dilatometric measurements discovered effect of increasing ammount of ZrO2 in BaTiO3. Rising amount of ZrO2 had a lowering effect on initial sintering temperature and materials achieved higher relative densities. This was also true for samples sintered using SPS, where it was less obvious. Measuring of electrical properties discoverad electric conductivity for SPS sintered samples, which was most probably caused by carbon introduced into samples during SPS cycle.

This thesis deals with fabrication and optimization of lead-free piezoceramics based on (Ba0,85Ca0,15Zr0,1Ti0,9)O3 (BCZT). The BCZT precursor powder was synthesized by sol-gel method. Dependence of relative density, microstructure, phase structure and piezoelectric properties on the sintering temperature in a range from 1300–1500 °C was studied on disc shaped samples, which were prepared by cold isostatic pressing (CIP) using pressure of 700 MPa. It was found, that sintering at 1300 and 1350 °C leads to ceramics with fine-grain microstructure, which exhibits poor piezoelectric properties (d*33 = 50 pC·N1 and 65 pC·N1, respectively). The highest value of piezoelectric charge coefficient was obtained by sintering at 1500 °C (d*33 = 390 pC·N1). Furthermore, BCZT thick films were prepared by tape casting. The composition of the ceramic slurry was optimized and various sintering techniques were tested to obtain completely flat films of BCZT ceramics. The correct sintering configuration has not been found. The least deformation of the films was achieved when the samples were sintered hung on the ZrO2 rod. The highest value of d*33 for BCZT films was measured when the sample was sintered at 1400 °C with the dwell time for 4 h (d*33 = 340 pC·N1).

This diploma thesis deals with the preparation of doped piezoceramic materials based on BaTiO3 using electrophoretic deposition. Five rare earth oxides, i.e. Er2O3, Dy2O3, Eu2O3, Tb407 and CeO2, were used as dopants in amounts of 1, 3, and 5 wt. %. The prepared deposits were evaluated in terms of preparation methodology, high temperature dilatometry, X-ray diffraction analysis, relative density, mean grain size, hardness and fractographic analysis. The study of dilatometric curves described the sintering behavior and its changes at different material compositions. X-ray diffraction analysis revealed a tetragonal phase in all samples; the tetragonality of the BaTiO3 crystalline cell decreased with dopant content. By a suitable choice of dopant, it was possible to significantly increase the relative density of sintered samples, their hardness and at the same time prevent the samples from coarsening of the microstructure during heat treatment. A relative density up to 98 %, a mean grain size below 1 m and a hardness of over 10 GPa were achieved. Analysis of the fracture surfaces revealed that the fracture mode was transcrystalline for the most of studied materials; only the samples doped with cerium dioxide had fracture surfaces with both transcrystalline and intercrystalline fracture modes. Based on the obtained results, a suitable composition of the material for the intended use in a layered piezoceramic harvester was identified, which, in addition to the BaTiO3 layers, consists of functionally-protective Al2O3 and ZrO2 layers.

The thesis focuses on the development of instruments used for surfaces and nanostructures characterization. Individual techniques of scanning probe microscopy provide different information of the sample surface. The resolution of scanning probe microscopy, providing 3D topography information, reaches subnanometer values or even an atomic level. Therefore, the scanning probe microscopy is one of the most employed method in the field of nanotechnology. The thesis describes the details of development of two scanning probe microscopes intended for measurement under ultra high vacuum conditions. As for the first one, many changes were proposed leading to its better variability, extended functionality and increased user comfort. The second microscope is being design with the aim of its combination with other analytic techniques, especially with scanning electron microscopy. An integral part of scanning probe microscopes is a precise positioning system for navigation of the probe to the selected site. Therefore, the thesis also deals with the development of linear piezoceramic actuators used not only in the ultra high vacuum compatible microscopes but also as a general purpose nanomanipulators.

Master’s Thesis deals with obtaining electricity from the vibrations of the surrounding environment through piezoelectric vibration generator. To simulation piezoceramics and design mechanical parts of the generator was used simulation program ANSYS 10.0. First, parameters of the designed piezoelectric generator were numerically calculated, and then these values were compared with the real sample. Further work is in the description of material properties of piezo materials.

The topic of this thesis is synthesis and preparation of lead-free pizoceramic with perovskite structure, in particular potassium-sodium niobate (KNN). In theoretical part are described possibilities of KNN synthesis and of it’s shaping and sintering. Experimental part deals with three types of synthesis described in the theretical part – solid state reaction, hydrothermal synthesis, sol-gel synthesis, and subconsequentional shaping of prepared powders by uniaxial pressing, cold isostatic pressure method, sintering (classical in oven, in some cases SPS – spark plasma sintering) of such green body and their following properties like relative density, grain size or charge constant. Preparation of KNN powder by each described method took place, followed by shaping and sintering. Best properties were shown by SPS sintered samples, which reached the highest density and lowest grain growth.

The content of this thesis is about preparation and processing of lead-free piezoceramic materials with perovskite structure. Potassium sodium niobate (KNN) powder was prepared by solid state reaction (SSR) and liquid phase reaction (sol-gel reaction). The powders were formed by uniaxial and isostatic pressing and further sintered. The density, grain size and morphology were determined on the sintered samples. The powder, synthesised by SSR and sintered in a conventional furnace, was chosen as a standard. The maximum density achieved on samples after optimization of sintering cycle was 93 %TD. The sintering optimization involved a homogenization step at 950 °C, which promotes the correct development of the phase composition and microstructure, followed by sintering at 1120 °C. The same approach and sintering cycle were used for sintering the samples, prepared by sol-gel synthesis. The maximum density of the samples prepared by sol-gel reaction and sintered in a conventional way, was 92 %TD. For further comparison, both of the synthesised powders were sintered using SPS (spark plasma sintering), which increased their final density up to 97 %TD. The approximate value of the piezoelectric coefficient d33 (pC/N) has been measured on selected SSR samples with pure phase composition ((K0,5Na0,5)NbO3). The best measured value of d33 was around 100 pC/N.

The main objective of the presented thesis is to contribute to the development of diagnostic methods for piezoelectric sensor testing. The thesis describes the methods for piezoelectric sensors microcracks identification and diagnostics. The core of the thesis presents the development of a knock sensor prototype, design of suitable methods for the knock sensors diagnosis and evaluation of developed methods with focus on detection of microcracks in the sensor piezoceramic. The last part of the thesis deals with the influence of cracks and splits on the measured data from the piezoelectric transducer. The presented methods are focusing on impedance measurements and sensors frequency response measurements. Known properties of used piezoelectric material as an information source for measurement and diagnosis are provided. The main result of the work is the evaluation of the methods developed for the piezoelectric sensors self-diagnosis.