Tellurite glass prodn. in gold melting crucible - which is stirred with gold stirref under pure oxygen atmos

摘要

Tellurite glass for opt. instrument mfr. is prepd. by melting a tellurite glass mixt., pref. contg. 50 mole % TeO2, in an Au melting crucible and in an O2 gas atmos. and pref. stirring mixt. during melting with an Au stirrer. Glass is pref. melted at 750-800 degrees C for 7-8 hrs., with stirring, to defoam and clarify; cooled to 600 degrees C with stirring for 1 hr.; removed from furnace and cast into a pre-heated mould and cooled slowly. O2 prevents reduction of TeO2 and formation of fine metallic crystal grains, usually caused through use of Au melting appts. Glass obtd. is transparent and free from light-scattering particles.