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Controlled Crystallization in Self‐Reinforced Silicon Nitride with Y 2 O 3 , SrO, and CaO: Crystallization Behavior
Author(s) -
Hwang C. James,
Susnitzky David W.,
Newman Robert A.,
Beaman Donald R.,
Pyzik Aleksander J.
Publication year - 1995
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.1151-2916.1995.tb09085.x
Subject(s) - crystallization , materials science , chemical engineering , amorphous solid , silicon nitride , phase (matter) , mineralogy , silicon , crystallography , chemistry , metallurgy , organic chemistry , engineering
The controlled crystallization of the amorphous grain boundary phase has been examined in a series of self‐reinforced Si 3 N 4 materials with added Y 2 O 3 , SrO, and CaO. The effects of time, temperature, atmosphere, glass content, glass chemistry, and matrix Si 3 N 4 on the crystallization have been investigated. The stability of the crystallized product, the crystallization kinetics ( T‐T‐T curve), and crystallization mechanisms have also been examined. Crystallization produced an oxynitroapatite containing Y, Sr, and Ca over a broad range of heat‐treatment conditions and glass compositions. The oxynitroapatite was compatible with Si 3 N 4 and remained stable up to 1600°C. At low temperatures (<1350°C), the rate‐limiting crystallization mechanism was oxygen diffuson in the glass, and at higher temperatures (>1350°C) the rate‐limiting crystallization step changed to either the formation of new Si 3 N 4 grains or solute diffusion in the glass.