Density and Surface Tension of Binary Ferrite Melts

Abstract

The density and the surface tension of Na2O-Fe2O3 and RO(R=Ca, Sr, Ba)-Fe2O3 melts have been measured to investigate the structure of these melts. Fe3+-ions may be amphoteric ions in these melts, that is, an oxygen 4 coordinated Fe3+ ion forms an oxygen complex anion such as SiO2 and an oxygen 6 coordinated Fe3+ ion acts as a cation. The size of oxygen complex anion which can be calculated from the density and the surface tension using the Reiss’s theory is about 0.5−1.5×10−9 m and increases with increasing RO content. Especially in the BaO-Fe2O3 system the size of oxygen complex anion has a maximum value at 50 mol%BaO. Infrared absorption spectra of quenched glassy samples show a good correspondence to the dependence of complex anion size upon the composition.