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Hydrogen profiles in the surface of reduced lead‐silicate glasses
Author(s) -
Rigato V.,
Mea G. Della,
Pantano Carlo G.
Publication year - 1994
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740210213
Subject(s) - adsorption , microporous material , hydrogen , annealing (glass) , silicate , alkali metal , materials science , chemical engineering , chemistry , lead (geology) , kinetics , inorganic chemistry , mineralogy , composite material , organic chemistry , quantum mechanics , engineering , geomorphology , geology , physics
It is shown that the thermochemical reduction of alkali‐lead‐silicate glass does not lead to any significant incorporation of hydrogen in the surface, but greatly sensitizes the surface to the chemical and physical adsorption of water. The treatment creates a thin (25 nm) compositionally modified layer of silica‐rich, perhaps microporous, glass at the surface where the hydrogen concentration due to adsorption is irreversible. A more uniform, in‐depth hydrogen profile that extends thousands of angstroms into the treated surface is reversible. The time and temperature of thermochemical treatment influence the initial kinetics of the adsorption. These observations are of practical significance to the behavior of electron multiplier and microchannel plate devices that have been exposed to humid environments. It is demonstrated that vacuum annealing after heat treatment can be used to limit the rate and extent of water adsorption.