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New Strategies for Preparing NanoSized Silicon Nitride Ceramics
Author(s) -
Xu Xin,
Nishimura Toshiyuki,
Hirosaki Naoto,
Xie RongJun,
Zhu Yinchun,
Yamamoto Yoshinobu,
Tanaka Hidehiko
Publication year - 2005
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.1551-2916.2005.00187.x
Subject(s) - spark plasma sintering , materials science , silicon nitride , nanocrystalline material , sintering , ceramic , amorphous solid , chemical engineering , silicon , nitride , phase (matter) , metallurgy , composite material , nanotechnology , crystallography , chemistry , organic chemistry , layer (electronics) , engineering
We report the preparation of nanosized silicon nitride (Si 3 N 4 ) ceramics via high‐energy mechanical milling and subsequent spark plasma sintering. A starting powder mixture consisting of ultrafine β‐Si 3 N 4 and sintering additives of 5‐mol% Y 2 O 3 and 2‐mol% Al 2 O 3 was prepared by high‐energy mechanical milling. After milling, the powder mixture was mostly transformed into a non‐equilibrium amorphous phase containing a large quantity of well‐dispersed nanocrystalline β‐Si 3 N 4 particles. This powder precursor was then consolidated by spark plasma sintering at a temperature as low as 1600°C for 5 min at a heating rate of 300°C/min. The fully densified sample consisted of homogeneous nano‐Si 3 N 4 grains with an average diameter of about 70 nm, which led to noticeable high‐temperature ductility and elevated hardness.