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Desintering Process in the Gas‐Pressure Sintering of Silicon Nitride
Author(s) -
Hwang ShyhLung,
Becher Paul F.,
Lin HuaTay
Publication year - 1997
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.1151-2916.1997.tb02834.x
Subject(s) - sintering , crucible (geodemography) , materials science , silicon nitride , nitride , boron nitride , ceramic , nitrogen , dissolution , graphite , silicon , partial pressure , metallurgy , boron , chemical engineering , composite material , chemistry , oxygen , layer (electronics) , computational chemistry , organic chemistry , engineering
A unique desintering phenomenon has been observed in gas‐pressure sintering of silicon nitrides with additives of yttria and alumina. The desintering phenomenon occurred, simultaneous with weight increase, only when a boron nitride crucible was used in combination with the application of high nitrogen pressure (5 MPa). When the nitrogen pressure was low (0.5 MPa), or when the boron nitride crucible was replaced by a graphite crucible, this desintering phenomenon was not observed. These results could be rationalized by the chemical dissolution of nitrogen into the oxynitride melts and the resultant evolution of carbon monoxide. This indicates that the high nitrogen overpressure employed in gas‐pressure sintering of silicon nitride ceramics is not always beneficial.