Glass Formation in Multicomponent Phosphate Systems Containing TiO2

Glass formation was investigated in the Na2O–TiO2–P2O5, K2O–TiO2–P2O5, BaO–TiO2–P2O5,Na2O–BaO–P2O5, and Na2O–BaO–TiO2–P2O5 systems. In the Na2O–TiO2–P2O5 system, glass containing up to 45.5 mol% TiO2 was found to be formed at the composition of Na2O/P2O5=1, whereas in the K2O–TiO2–P2O5 system the glass formation was observed in a narrow region along the composition of K2O/P2O5=1 in a three-component diagram. In the BaO–TiO2–P2O5 system, only the glass containing about 10 mol% TiO2 as a maximum was obtained. In the Na2O–BaO–TiO2-P2O5 system, the region of glass formation extended with an increase of Na2O up to 30 mol%. These results suggested that a certain amount of Na2O is necessary for the formation of glass containing a large amount of TiO2 in the presence of BaO. The three-component diagrams of the Na2O–TiO2–P2O5 and Na2O–BaO–P2O5 systems indicated that the most favorable amount of Na2O for the glass formation in this four-component system is 27 to 28 mol%.