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Hot Corrosion of Silica
Author(s) -
Lawson Mark G.,
Kim Hei R.,
Pettit Fred S.,
Blachere Jean R.
Publication year - 1990
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.1151-2916.1990.tb05147.x
Subject(s) - crystallization , devitrification , materials science , corrosion , wetting , sodium sulfate , oxygen , chemical engineering , sodium oxide , temperature cycling , sodium , mineralogy , oxide , metallurgy , thermal , composite material , chemistry , physics , organic chemistry , engineering , meteorology
The high‐temperature corrosion of bulk silica glass was studied in pure oxygen and in SO 3 ‐containing oxygen atmospheres in the presence of liquid sulfate deposits at temperatures of 700° and 1000°C. No reaction and devitrification were observed without Na 2 SO 4 on the surface. The wetting of the silica by the sulfate, the tendency toward basic fluxing, and the crystallization of the silica incrased with the activity of Na 2 O. The most extensive degradation of vitreous silica occurred by crystallization, and the resulting spalling under basic conditions and thermal cycling at basic conditions were parabolic. This behavior is explained by a model in which the crystallization is controlled by sodium at the glass‐crystal interface and its diffusion into the glass. This sodium diffuses into the glass before crystallization and is swept ahead of the crystallization front.