The Impact of BaO Addition on the Structure and Microstructure of Glazes of the SiO2-Al2O3-CaO-MgO-Na2O system
PASIUT K. 1, PARTYKA J. 1, KOZIEN D. 1
1 AGH UST, Krakow, Poland
This work investigated the effect of barium oxide addition on the structure and microstructure of glazes from the SiO2-Al2O3-CaO-MgO-K2O multicomponent system. Barium oxide has been introduced into the glaze composition in 3 different amounts: 2.5; 5 and 7.5 by weight. The ground glazes were fired at a maximum temperature of 1240oC.
The glazes were subjected to phase composition and microstructure analyzes using a scanning electron microscope. Studies aimed at determining changes in the structure are measurements in the mid-infrared range using Raman spectroscopy. Characteristic temperatures were also determined, and mechanical strength as well as surface roughness of the obtained glazes were measured.
Analysis of the phase composition showed the presence of the diopside crystal phase in each of the glazes analyzed. The addition of barium oxide increased the amount of this crystalline phase and the appearance of the crystalline phase of hyalophane. Microstructure analysis showed the influence of the added barium oxide on the crystal habit. On the other hand, the analysis of the glaze structure, based on mid-infrared spectroscopic studies, showed the depolymerizing effect of barium cations. The color roughness and mechanical properties of the obtained glaze surfaces were also examined and related to the obtained results.