1983 Volume 24 Issue 1 Pages 35-41
Density, electrical conductivity, viscosity and surface tension have been measured to find out the behavior of Fe3+-ions in the molten Na2O–Fe2O3, RO–Fe2O3 (R=Ca, Sr, Ba) systems. In these melts Fe3+-ion may be an amphoteric ion, that is, the oxygen coordination number of Fe3+ is 4 and/or 6 (Fe3+(4) and/or Fe3+(6)). Fe3+(4) forms a complex anion with oxygen such as Si4+, and Fe3+(6) acts as a cation. Effects of Na2O and RO-content on the physical properties of ferrite melts have been discussed in term of the ratio of Fe3+(4) and Fe3+(6). The controlling factors of Fe3+(4)/Fe3+(6) ratio are the basicity and content of alkali, alkaliearth oxides. The distribution of Fe3+(4) and Fe3+(6) for the RO–Fe2O3 systems was assumed by considering the basicity and content of RO, and measured values of physical properties and IR-spectra of quenched glassy samples support this distribution. The rigid sphere diameter of anion in these melts calculated from the surface tension and the density using the Reiss-s theory also provides a good agreement with the change in the Fe3+(4)/Fe3+(6) ratio.
