Irena Wacławska

Effect of copper addition on glass transition of silicate–phosphate glasses

Glass transformation effect of mixed SiO2–P2O5–K2O–MgO–CaO–CuO glasses was studied by DSC, XRD, SEM, and Raman spectroscopy methods. The relationship between the parameters characterizing glass transformation effect and an amount of phosphorous and copper forming the glassy structure was discussed. It was shown that an increasing content of phosphorous increased solubility of copper in the structure of the studied glasses which was the result of P–O–Cu bonds formation. Degree of changes of Tg, ∆cp, and time of relaxation values were higher in glasses with higher content of P2O5 and CuO. The observed relations were explained on the basis of the local atomic interactions in the structure of glass.

Characterization of thermally induced of crystalline phases in CuO-containing silicate–phosphate glasses

The DSC, XRD, FTIR, and 31P MAS-NMR methods were applied to study complex crystallization processes occurring during the thermal treatment of multicomponent SiO2–P2O5–K2O–CaO–MgO glasses modified by the addition of variable amount of copper. The crystallization temperatures were found to decrease with the increasing copper content. The products of multistage crystallization identified by XRD and characterized by FTIR and NMR are the Ca9KMg(PO4)7 and Ca19Cu2(PO4)14 phosphates of whitlockite-type, and the CaMgSi2O6 and Cu0.69Mg1.31Si2O6 silicates of diopside type.

Structural role of Fe in the soil active glasses.

Glasses of the SiO(2)-P(2)O(5)-K(2)O-MgO-CaO-Fe(2)O(3) system acting as slow release fertilizers were synthesized by the melt-quenching technique. The influence of iron addition on the structure of glasses was evaluated by FTIR spectroscopy (with spectra decomposition) and (57)Fe Mössbauer spectroscopy. The chemical activity of glasses in the 2 mass% citric acid solutions was measured by the ICP-AES method. It has been found that the formation of domains with structure similar to phosphates with chemically stable P-O-Fe(3+) and P-O-Fe(2+) bonds decreases the glass solubility under conditions simulating the soil environment.

DTA and X-ray diffraction study of the phase transformation of silica minerals

Abstract Results of the investigations of the quartz polymorphous transformation by means of the DTA and X-Ray method have been presented. The influence of quantity and a type of isomorphous substitutions on temperature and kinetics, of transformation into high temperature cristobalite was determined. Usefulness of DTA and Z-Ray as a method of quantitative determination of quartz and cristobalite is discussed.