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Effects of yttria and magnesia on densification and thermal conductivity of sintered reaction‐bonded silicon nitrides
Author(s) -
Zhou You,
Hyuga Hideki,
Kusano Dai,
Matsunaga Chika,
Hirao Kiyoshi
Publication year - 2019
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.16015
Subject(s) - sintering , materials science , thermal conductivity , silicon nitride , ceramic , yttria stabilized zirconia , nitride , atmospheric temperature range , silicon , doping , conductivity , magnesium , analytical chemistry (journal) , mineralogy , chemical engineering , metallurgy , composite material , cubic zirconia , chemistry , organic chemistry , physics , optoelectronics , layer (electronics) , engineering , meteorology
A variety of combinations of Y 2 O 3 and MgO were used as additives in preparing Si 3 N 4 ceramics by the sintering of reaction‐bonded silicon nitride (SRBSN) method. By varying the amount of Y 2 O 3 in the range of 0‐5 mol% and that of MgO in the range of 0‐8 mol%, the effects of Y 2 O 3 and MgO additives on nitridation and sintering behaviors as well as thermal conductivity were studied. It was found that appropriate amount and combination of Y 2 O 3 and MgO additives were essential for attaining full densification and achieving high thermal conductivity. The sample doped with 2.5 mol% of Y 2 O 3 and 5 mol% of MgO attained a thermal conductivity of 128 Wm −1 K −1 when sintered at 1900°C for 6 hours, and the sample doped with 2 mol% of Y 2 O 3 and 4 mol% of MgO achieved a thermal conductivity of 156 Wm −1 K −1 when sintered for 24 hours.