Ba(Ti1-xZrx)2O5 Glasses Prepared by Containerless Aerodynamic Levitator

초록

Levitation technique is of interest field because it enables sample be melted and solidified without a container. Melting experiments under microgravity provides a peculiar environment characterized by no thermally-induced convection, no sedimentation/buoyancy and non-contact with vessel walls. Because a melting experiment under the microgravity environments incurs a high cost, it is an essential prerequisite to conduct a ground-based melting experiment using a levitation technique. Levitation techniques are classified in terms of the levitation source that counteracts the gravitational force on the samples. Typical levitation techniques include aerodynamic, electrostatic, acoustic, and electromagnetic levitation. Among these techniques, aerodynamic levitation is economical and can be used for investigations of ceramic materials. Containerless aerodynamic levitation processing suppresses inhomogeneous nucleation from the container walls. As a result, the deeply undercooled melt easily transforms to a glassy state compared with conventional glass making process. The development of new glasses with higher refractive indices is of great interest. Thus, TiO2-based high reflective index glasses have been investigated in literature. In order to develop a new optical materials with high refractive indices and small wavelength dispersion, Ba(Ti1-xZrx)2O5 glasses were prepared by aerodynamic levitation. Samples with various compositions were levitated using O2 gas flow in an aerodynamic levitator and melted using a CO2 laser. The levitated melts were rapidly cooled to room temperature and solidified by turning off the CO2 laser. Colorless and transparent Ba(Ti1-xZrx)2O5 glasses were obtained. The thermal characteristics and optical properties of Ba(Ti1-xZrx)2O5 glasses were investigated and the results were discussed in detail.