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High‐Temperature Strength of Sinter‐Forged Silicon Nitride with Lutetia Additive
Author(s) -
Kondo Naoki,
Asayama Masahiro,
Suzuki Yoshikazu,
Ohji Tatsuki
Publication year - 2003
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.1151-2916.2003.tb03489.x
Subject(s) - materials science , forging , silicon nitride , grain boundary , microstructure , silicon , composite material , grain growth , metallurgy , phase (matter) , nitride , sintering , layer (electronics) , chemistry , organic chemistry
A sinter‐forging technique was successfully applied to fabricate a silicon nitride with a lutetia (Lu 2 O 3 ) additive. The sinter‐forged specimen had a strongly anisotropic microstructure where rodlike silicon nitride grains preferentially aligned perpendicular to the forging direction. The specimen exhibited superior strength of ∼700 MPa at 1500°C. This strength was highest when compared with previous silicon nitrides at temperatures >1400°C. Such superior high‐temperature strength was attributed to grain alignment as well as to the refractory grain‐boundary glassy phase and the existence of glass‐free grain boundaries.