caa a22 4500 463225376 CHVBK 20180405153225.0 cr unu---uuuuu 170326e20070601xx s 000 0 eng 10.1007/s10853-006-1232-z doi (NATIONALLICENCE)springer-10.1007/s10853-006-1232-z Containerless processing of a lithium disilicate glass [Elektronische Daten] [K. Ranasinghe, C. Ray, D. Day, J. Rogers, R. Hyers, T. Rathz] Glasses of Li2O·2SiO2 (LS2), and LS2 doped with 0.001wt% platinum (LS2+0.001wt% Pt) compositions were melted, cooled and reheated at controlled rates while levitated (containerless) inside an electrostatic levitator (ESL) furnace at the NASA Marshall Space Flight Center. The experiments were conducted in vacuum using spherical, 2.5-3mm diameter, glass samples. The measured critical cooling rate for glass formation, R c, for the LS2 and LS2+0.001wt% Pt glasses processed at ESL were 14±2°C/min and 130±5°C/min, respectively. The values of R c for the same LS2 and LS2+0.001wt% Pt glasses processed in a container were 62±3°C/min and 162±5°C/min, respectively. The effective activation energy for crystallization, E, for this LS2 glass processed without a container at ESL, was higher than that for an identical glass processed in a container. These results suggest that the glass formation tendency for a containerless LS2 melt is significantly increased compared to an identical melt in contact with a container. The absence of heterogeneous nucleation sites that are inherently present in all melts held in containers is believed to be the reason for the increased glass forming tendency of this containerless melt. Springer Science+Business Media, LLC, 2007 Ranasinghe K. Department of Physics and Geology, Northern Kentucky University, Nunn Drive, 41099, Highland Heights, KY, USA aut Ray C. Marshall Space Flight Center, National Aeronautics and Space Administration, 35812, Huntsville, AL, USA aut Day D. Graduate Center for Materials Research, University of Missouri-Rolla, 65409, Rolla, MO, USA aut Rogers J. Marshall Space Flight Center, National Aeronautics and Space Administration, 35812, Huntsville, AL, USA aut Hyers R. Department of Mechanical and Industrial Engineering, University of Massachusetts, 01003, Amherst, MA, USA aut Rathz T. University of Alabama in Huntsville, 35899, Huntsville, AL, USA aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/12(2007-06-01), 4291-4297 0022-2461 42:12<4291 2007 42 10853 https://doi.org/10.1007/s10853-006-1232-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1232-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ranasinghe K. Department of Physics and Geology, Northern Kentucky University, Nunn Drive, 41099, Highland Heights, KY, USA aut NATIONALLICENCE 700 1- Ray C. Marshall Space Flight Center, National Aeronautics and Space Administration, 35812, Huntsville, AL, USA aut NATIONALLICENCE 700 1- Day D. Graduate Center for Materials Research, University of Missouri-Rolla, 65409, Rolla, MO, USA aut NATIONALLICENCE 700 1- Rogers J. Marshall Space Flight Center, National Aeronautics and Space Administration, 35812, Huntsville, AL, USA aut NATIONALLICENCE 700 1- Hyers R. Department of Mechanical and Industrial Engineering, University of Massachusetts, 01003, Amherst, MA, USA aut NATIONALLICENCE 700 1- Rathz T. University of Alabama in Huntsville, 35899, Huntsville, AL, USA aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/12(2007-06-01), 4291-4297 0022-2461 42:12<4291 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer