Effects of La2O3 on Viscosity and Structure of SiO2-CaO-Al2O3-MgO Melt.

For the meting process of glass-ceramics, the melts are simulated by using analytically pure materials high temperature. The effects of La2O3 on the viscosity and structure for the CaO-SiO2-MgO-Al2O3 melt are studied via both rotating-cylinder method and Raman spectroscopy. The results show that the viscosity and viscous flow activation energy decreases as the La2O3 content increases. The addition of La2O3 destroyed the silicate structural units(Qn)m the met. The percent of Q¹,Q² units increases with increasing amount of La2O3. However, the percent of Q³ units decreases with increasing amount of La2O3. In addition, the percent of Q0 units are slightly dependent on the La2O3 content. It indicates that the addition of La2O3 increase the number of non-bridging oxygen in the state structural units and reduce the degree of polymerization. La2O3 pay a role as network modifier in the melt. [ABSTRACT FROM AUTHOR]