Magdalena Leśniak

The effect of SiO2/Al2O3 ratio on the structure and microstructure of the glazes from SiO2–Al2O3–CaO–MgO–Na2O–K2O system

Ceramic glazes are commonly used to covering of the facing surface of ceramics ware. A well-chosen oxide composition and firing conditions of glazes causes significant improvement of technical parameters of ceramic products. Modern glazes are classified as glass-ceramic composites with different crystalline phases arising during firing. The presence of crystals in the glass matrix is influenced by many factors, especially by oxides molar composition. A crucial role is played by the molar ratio of SiO₂/Al₂O₃. In this work the six composition of glazes from SiO₂-Al₂O₃-CaO-MgO-Na₂O-K₂O system were examined. The only variable is the ratio of the silicon oxideto alumina at a constant content of other components: MgO, CaO, K₂O, Na₂O, ZnO. In order to determine the real phase composition of the obtained glazes research on fluorescence spectrometer (XRF) were done. For structural studies X-ray diffraction (XRD) and spectroscopic in the middle infrared (MIR) were performed. In order to determine the state of the surface (microstructure) research on the scanning electron microscope (SEM) with EDX. The research allowed to determine the influence of SiO₂/Al₂O₃ ratio on the structure and phase composition of glazes and the nature, and type of formed crystalline phases.

Raman and infrared spectroscopy study on structure and microstructure of glass-ceramic materials from SiO2-Al2O3-Na2O-K2O-CaO system modified by variable molar ratio of SiO2/Al2O3.

This paper is focused on the effect of the molar ratio of SiO2/Al2O3 on the microstructure and structure of the internal aluminium-silicon-oxide lattice of the glass-ceramic materials from the SiO2-Al2O3-Na2O-K2O-CaO system. In order to examine the real composition of the obtained samples, a chemical analysis was performed. Following the heat-treatment procedure, pseudowollastonite, anorthite and the vitreous phase were identified. In order to determine the microstructure, research using the scanning electron microscope (SEM) with EDS was done. For the inner structural study, X-ray diffraction (XRD), Raman spectroscopy as well as MIR and FIR spectroscopy were performed.

Thermal characterisation of raw aluminosilicate glazes in SiO2–Al2O3–CaO–K2O–Na2O–ZnO system with variable content of ZnO

Abstract Thermal properties of raw aluminosilicate ceramic glazes in the multicomponent system of SiO2–Al2O3–CaO–K2O–Na2O–ZnO modified by ZnO addition were studied by differential thermal analysis (DTA), dilatometry (DIL), hot-stage microscopy (HSM), X-ray diffraction and fourier transform infrared spectroscopy (FTIR). Using the method of differential thermal analysis, the ways in which zinc oxides affect the temperature of transition (Tg), crystallisation (Tc) were determined. An analysis of the DTA data obtained during thermal tests showed that an increase in ZnO content results in decreasing the Tg value. Also, the influence of ZnO on characteristic temperatures and viscosity of glazes was checked. The introduction of zinc oxide (ZnO) into the glaze composition contributes to the decrease in viscosity of such glazes. An increasing ZnO content in the glazes also causes the reduction in softening (Ts), half-sphere (Thalf-sphere) and fusion (Tfusion) temperatures. The mid-infrared spectroscopy showed that the thermal properties of glazes in SiO2–Al2O3–CaO–K2O–Na2O–ZnO system modified by addition of ZnO can be associated with the depolymerising influence of zinc ions on the structure of the tested glazes.

Investigation on Bioactivity of Zirconium-Calcium Coatings on Titanium Surface Obtained by Sol-Gel and Electrophoretic Deposition (EPD) Methods

The aim of the study was to obtain zirconium and calcium doped zirconium coatings using sol-gel methodology and their further modification with electrophoretically deposited hydroxyapatite. Both systems phase composition was investigated using Raman spectroscopy. Their morphology and composition was studied using scanning electron microscope (SEM) with X-ray microanalysis (EDS), while their topography was observed using atomic force microscope (AFM). The osseointegrative properties of both coatings were investigated using in vitro Simulated Body Fluid (SBF) test. The resulting systems were studied using the same methods that were applied to the two coatings.