Metal fluoride glasses esp. for infrared optics - are based on zirconium or hafnium tetrafluoride with addition of other metal fluorides

摘要

Fluoride glass is based on a glassy tert. system of metal fluorides having a general compsn. a = moles of component A; b = moles of component B, and c= moles of component C, where a+b+c =1. The glass of the component A is ZrF4 or HyF4 (0.52-0.63 moles), B is BaF2 (0.27-0.38 moles) and C is ThF4 or UF4 or a mixt. of these two (0.02-0.15 moles). The ThF4 or UF4 of component C is pref. substitd. by a fluoride of the rare earth metals, component A being present in an amt. 0.56-0.64 moles, B in an amt. 0.30-0.36 moles and C in an amt. 0.02-0.12 moles. The glass is resistant to attack from moisture, F2, ClF3, UF6, and HF, and withstands heating in air to 350 degrees C. The glass has high transparency in the infrared region (to 8 mu m). Cheap metal oxides can be used in prodn. of the glass, by adding NH4. nHl= and effecting the conversion of the oxides to the fluorides during the melting.