Physical Properties of Multicomponent Fluorohafnate Glasses
Résumé
Fluoride glasses based on HfF4 have been synthesized in the HfF4-SrF2-BaF2 system. In order to decrease the crystallization rate, various fluorides (PbF2, ZnF2, AlF3 and YF3) have been introduced in the 66HfF(4)-22SrF(2)-12BaF(2) composition as substituent of alkali earth cations. Glass transition temperature is close to 320 degrees C, and coefficient of thermal expansion is 155 10(-7) K-1. Microhardness and elastic moduli have been measured. Values of refractive index are given for wavelengths ranging from 633 nm to 1551 nm. By comparison to fluorozirconates, fluorohafnate glasses exhibit larger density, lower refractive index, lower phonon energy and extended transmission in the mid-infrared spectrum. Potential applications relate to active optical fibres and supercontinuum generation