Vijaya Kumar
University of Mysore, India
Title: Fabrication, optical and thermal properties of glass and crystalline rare-earth aluminates
Biography
Biography: Vijaya Kumar
Abstract
Recently, research on bulk glass and glass-ceramics has attracted the attention due to their low cost optical materials of the future. Alumina based ceramics have wide significant applications because of their refractory nature, high hardness, high strength, transparency in the infra-red region and resistant to chemical attack. Conventionally, rare earth perovskites were prepared by melting process or by sintering techniques because of their refractory nature and recently prepared through several low temperature solution routes. Conventionally, it is difficult to vitrify them without using the network forming agents. In this study, Aero-Dynamic Levitator (ADL) was used to undercool the melt well below the melting temperature. The formation of bulk spherical glass and crystalline RAlO3 (R=rare-earths) phases has been investigated due to their unique features in terms of the solidification process, glass structure and optical properties. RAlO3 sample was levitated by an ADL and completely melted by a CO2 laser and then cooled by turning off the CO2 laser and solidified. Among the rare earth aluminum perovskites, La, Nd and Sm aluminum perovskites solidified as glass and Eu to Lu aluminum perovskites solidified as crystalline phases. The NdAlO3 glass phase showed a high refractive index of ~1.89, suggesting that container less levitation is an elegant technique for fabrication of new glass and crystalline ceramics from an undercooled melt.
Recent Publications
Vijaya Kumar MS, Kuribayashi K, Yu J, Okada JT, Ishikawa T (2013) Microstructure and magnetic properties of metastable RFeO3 (R: Rareâ€earth element) formed from undercooled melt, J. Am. Ceram. Soc. 96: 995â€1002.
Vijaya Kumar MS, Okada JT, Ishikawa T, Paradis PF, Watanabe Y (2014) Density measurement of glass and liquid CaAl 2O4 using a pressurized electroâ€static levitator. Meas. Sci. Tech. 25:085301â€6.
Girish HN, Vijaya Kumar MS, Byrappa K, Basavalingu B (2015) Hydrothermal synthesis of some of the lanthanide aluminium perovskites – LnAlO3 (Ln=La, Sm & Gd), Mat. Res. Innov. 19: 270â€74
Sakata K, Watanabe Y, Okada JT, Vijaya Kumar MS, Paradis PF, Ishikawa T (2015), FTâ€IR emissivity measurements of Nb melt using an electrostatic levitation furnace, J. Chem. Thermody. 91:116â€120
SanSoucie MP, Rogers JR, Vijaya Kumar MS, Rodriguez J, Xiao X, Matson DM (2016) Effects of environmental oxygen content and dissolved oxygen on the surface tension and viscosity of liquid nickel, Int. J. Thermophys. 37:76 1â€11