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Improved thermal conductivity of β‐Si 3 N 4 ceramics by lowering SiO 2 /Y 2 O 3 ratio using YH 2 as sintering additive
Author(s) -
Wang Weide,
Yao Dongxu,
Liang Hanqin,
Xia Yongfeng,
Zuo Kaihui,
Yin Jinwei,
Zeng YuPing
Publication year - 2020
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/jace.17271
Subject(s) - ceramic , sintering , thermal conductivity , materials science , analytical chemistry (journal) , mineralogy , grain boundary , metal , doping , conductivity , grain size , metallurgy , microstructure , chemistry , composite material , optoelectronics , chromatography
A two‐step sintering process was conducted to produce β‐Si 3 N 4 ceramics with high thermal conductivity. During the first step, native SiO 2 was eliminated, and Y 2 O 3 was in situ generated by a metal hydride reduction process, resulting in a high Y 2 O 3 /SiO 2 ratio. The substitution YH 2 for Y 2 O 3 endow Si 3 N 4 ceramics with an increase of 29% in thermal conductivity from 95.3 to 123 W m −1 K −1 after sintered at 1900°C for 12 hours despite an inferior sinterability. This was primarily attributed to the purified enlarged grains, devitrified grain boundary phase, and reduced lattice oxygen content in the YH 2 ‐MgO‐doped material.