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Suppression of crystallization in ZBLAN glass by rapid heating and cooling processing
Author(s) -
Ong TengCheong,
Fogarty Ben,
Steinberg Ted,
Jaatinen Esa,
Bell John
Publication year - 2019
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/ijag.13096
Subject(s) - zblan , devitrification , materials science , amorphous solid , crystallite , crystallization , optoelectronics , composite material , analytical chemistry (journal) , chemical engineering , metallurgy , fiber , fiber laser , crystallography , chemistry , chromatography , engineering
ZBLAN glass is a heavy metal fluoride glass that tends to undergo heavy devitrification, resulting in a crystalline material. It has many applications, including its use as an optical waveguide for fiber‐optic technology. However, when the glass is processed with traditional casting techniques, crystallites form readily that act as scattering centers, which results in large attenuation losses. In this study, it has been experimentally demonstrated that processing ZBLAN rapidly with a heating rate of 25 000 K/min and cooling rate of 4000 K/min yields test samples that are fully amorphous and retain a disordered molecular arrangement characteristic of its molten state. This novel method was developed using a specifically designed equipment named a Rapid Electro‐thermal Processing Device, or “ REPD .” The REPD applies ohmic heating and thermal conduction to a heat sink to rapidly process the ZBLAN material. The absence of crystallites in the rapidly processed ZBLAN test samples were verified using transmission electron microscopy ( TEM ) analysis. Applying a theoretical algorithm, the critical cooling rate for yielding fully amorphous ZBLAN glass was determined to be 1081 K/min for a sample volume of 9.4 × 10 −8 m 3 .