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High‐Temperature Chemical Phenomena Affecting Silicon Nitride Joints
Author(s) -
BRITTAIN R.D.,
JOHNSON S.M.,
LAMOREAUX R.H.,
ROWCLIFFE D.J.
Publication year - 1984
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.1151-2916.1984.tb19163.x
Subject(s) - vaporization , silicon nitride , silicon , materials science , oxide , nitride , silicon oxide , ceramic , degradation (telecommunications) , chemical engineering , composite material , metallurgy , chemistry , layer (electronics) , organic chemistry , engineering , telecommunications , computer science
Knudsen cell mass spectrometry was used to study the chemical processes responsible for joint degradation in joined silicon nitride ceramics. Vapor species present above two commercial hot‐pressed silicon nitrides and above three joining glasses were identified, and partial pressures were estimated at 1480 K. Oxide vaporization products related to reducing conditions were observed. The implications of these results on proposed silicon nitride joining processes are discussed. It appears that oxygen potential gradients within both glazed and unglazed hot‐pressed Si 3 N 4 samples are responsible for the enhanced vaporization rates of the sample and the observed instability of glazed joints at high temperatures. Observed vaporization behavior of oxide additives correlates well with that predicted for the chemically reducing environment of Si 3 N 4 .