Evaporation and Convection from Glass Melts under low and high g — Drop Shaft and Aircraft Experiments —

Abstract

Evaporation and convection experiments on a 80PbO-20B2O3 (mol%) melt held on a platinum wire were conducted under microgravity in a drop shaft (490m free fall. 10-4g, 10sec) and on an aircraft (10-2g, 20sec). Companion experiments were also conducted at 2 g by banking the aircraft at 60 degree. Material evaporated from the melt on the platinum wire in a radial direction in the drop shaft experiments and condensed as small spherical particles on the glass enclosure. The gravity level affected the convection pattern of the evaporated material (panicles) in the aircraft experiments. The small glass particles collected on the surface of the glass enclosure were analyzed with a scanning electron microscope and electron probe microanalyzer. Uniform spherical particles (from 0.2 to 0.3 micrometers) were produced under microgravity while deformed particles of variable diameter (from 0.1 to 1 micrometer) were produced under 2 g.