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Effect of Nitriding on Electrolysis and Devitrification of High‐Silica Glasses
Author(s) -
ELMER T. H.,
NORDBERG M. E.
Publication year - 1967
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1967.tb15108.x
Subject(s) - devitrification , materials science , nitriding , cristobalite , electrolysis , alkali metal , quartz , metallurgy , crystallization , mineralogy , chemical engineering , composite material , chemistry , electrode , organic chemistry , layer (electronics) , electrolyte , engineering
Devitrification occurs near the cathode when reconstructed high‐silica glasses and fused quartz undergo electrolysis at 900°C. The crystalline phase is cristobalite and results from a concentration of alkali ions. Subsequent and more superficial crystallization around the alkali‐rich spot is caused by interaction of the glass with alkali vapors coming from the central spot. The degree of devitrification increases with the alkali content of the glass. Devitrification at constant alkali level can be reduced in reconstructed glasses by nitriding the porous glass with ammonia at a high temperature before consolidation. Devitrification decreases and viscosity and electrical resistivity increase as the nitriding temperature increases 500° to 1000°C. Nitrided glasses are more resistant to electrolytically induced devitrification than is fused quartz.