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The paper presents the method of preparation YAG:Ce precursor powder with ability for synthesis at lower temperature. Mechanochemical processing of an initial powder mixture was used as a preliminary step for subsequent high-temperature treatment of the precursor. The specific surface area, phase composition and luminescence properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. It has been shown that YAG structure formed at lower temperature by 300• C in comparison to the reference specimen but luminescence intesity was dependant on temperature of powder synthesis. The highest luminescence intensity was observed for powders synthesised at 1650• C. Keywords: mechanochemical processing, phosphor, YAG:Ce garnet W artykule przedstawiono otrzymywanie proszku granatu YAG:Ce z zastosowaniem zmodyfikowanej metody reakcji w stanie stałym. Mieszanina proszków wyjściowych została poddana procesowi aktywacji mechanochemicznej celem zwiększenia jego reaktywności podczas syntezy wysokotemperaturowej. Zbadano wpływ aktywacji na powierzchnię właściwą wyjściowej mieszaniny proszków. Proszek wygrzewany w różnych temperaturach został poddany analizie fazowej (XRD) oraz obserwacji na mikroskopie skaningowym (SEM). Zbadano niektóre właściwości optyczne: absorpcję i luminescencję przy wzbudzeniu λ=450 nm. Wykazano, że w wyniku aktywacji mechanochemicznej proszku wyjściowego YAG następuje obniżenie temperatury otrzymywania jednofazowego granatu itrowo-glinowego o 300• C, natomiast intensywność luminescencji zależała od temperatury syntezy; najwyższą uzyskano po syntezie w 1650• C.

In this study, a series of Ca9Y(PO4)7 compounds doped with 5% of Eu ions and with different [Y]/[Ca] ratios was synthesized using the Pechini method.

The process of persistent luminescence or glow-in-the-dark – delayed emission of light of irradiated substance has long fascinated researchers, who made efforts to explain the underlying physical phenomenon as well...

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The aim of those research was to find out the technique of the car windshield glass waste utilization. The research was performed in cooperation with the Polish small company, active in the waste utilization. Manufacturing of the light weight aggregates (LWAs) for application in the building concrete has been chosen as an appropriate solution. The local coal mine slates, the fine-grained coal mine wastes and fly ash from the local power station were tried for making the suitable mixture for granulation and sintering. All waste materials were characterized for their granulation, chemical composition and thermal behavior (DTA, TG/DTG, linear changes). Several mixtures with various composition were prepared, milled, homogenized and pelletized with water addition and finally sintered at 950°C. Thermally treated granules were tested for their density, porosity and mechanical properties. Some specimens were observed in scanning microscope. It has been shown that by variation of the composition of the waste materials it is possible to produce aggregates with a large variety of mechanical properties and porosities.

The goal of this study was to investigate the origin of ferroelectricity in Bi4Ti3O12. The bismuth titanate Bi4Ti3O12 (BTO), which belongs to the Aurivillius family, is one of the most interesting compounds among the bismuth-based layered ceramics. BTO is a ferroelectric material with wide applications in the electronic industry, as capacitors, transducers, memory devices and sensors. Aurivillius structures are described with a general formula following form:Am-1Bi2BmO3m-1. BTO ceramic materials is an Aurivillius structure with m = 3. This ceramic materials were prepared by conventional mixed-oxide method of the solid state reaction. The temperature of the Bi4Ti3O12 sintering was selected on basis of thermogravimetric studies. The crystal structure of Bi4Ti3O12 was examined at room temperature with an X-ray diffraction method. Phase formation behavior was investigated using the differential thermal analysis (DTA) and the thermal gravimetric (TG). The microstructure was investigated by SEM method. Based on the Dorrian’s model, the value of displacements between bismuth ions and oxygen octahedra was calculated.

Manufacturing high purity polycrystalline YAlO3 (YAP) ceramics could replace monocrystalline YAP thus recently it is an interesting task for low cost producers of scintillators. The paper presents influence of different source of initial oxide powders (micro/nano powders of Y2O3 and Al2O3) and the method of their homogenization on the formation of a YAP phase. The solid state reaction method was used to prepare YAP powder or ceramic pellets. After preheating, all samples in the form of powders and pellets were heat-treated in the temperature range of 1050-1650 °C. DTA method was applied for examination of the phase crystallization in the tested system. X-ray diffraction method (XRD) was used for characterization of the phase composition. X-ray microanalysis (EDS) was used to control homogeneity in the small areas. Morphology of the resultant samples are presented on SEM pictures. The results show a significant influence of the starting powders on the homogeneity, purity and temperature of formation of the main phase.