Paper Title:
The Effect of Heat-Treatment on Thermal Conductivity of Silicon Nitride Ceramics
  Abstract

Alpha- or beta-Si3N4 powder with larger grain size was uses as starting material, and the effect of heat-treatment on thermal conductivity of Si3N4 ceramics using MgO, Y2O3 and SiO2 as sintering additives was investigated in terms of their microstructure and the amount of grain boundary phase. Most of the components derived from sintering additives existed as glassy phase in sintered Si3N4. After heat-treatment at 1950oC for 8 h, the amount of glassy phase significantly decreased, and then small amount of glassy phase existed in Si3N4 ceramics was crystallized as Y2O3 and Y2Si3N4O3. In the case of Si3N4 ceramics using SN-7 powder, thermal conductivity of heat-treated Si3N4 was around twice of the value of sintered Si3N4, and the thermal conductivity was increased from 41.4 to 87.2 W/m•K due to not only the reduction of grain boundary phase but also the grain growth. In the case of Si3N4 using SN-F1 powder, thermal conductivity of Si3N4 ceramics was also significantly increased from 36.0 to 73.2 W/m•K after heat-treatment. In this case, the reduction of grain boundary phase mainly affected the thermal conductivity of Si3N4 ceramics because the grain size of heat-treated Si3N4 was nearly the same as that of sintered Si3N4. The reduction of grain boundary phase from Si3N4 was effective for the improvement of their thermal conductivity in addition to grain growth of Si3N4.

  Info
Periodical
Edited by
Takashi Goto, Yi-Bing Cheng and Takashi Akatsu
Pages
52-56
DOI
10.4028/www.scientific.net/KEM.484.52
Citation
K. Yoshida, Y. Sekimoto, K. Katayama, T. Wasanapiarnpong, M. Imai, T. Yano, "The Effect of Heat-Treatment on Thermal Conductivity of Silicon Nitride Ceramics", Key Engineering Materials, Vol. 484, pp. 52-56, 2011
Online since
July 2011
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Hua Zhang Zhai, Hong Nian Cai, Xiao Zhan Yang, Jian Bao Li, Gang Feng Guo, Chuan Bao Cao
Abstract:A series of BN-SiO2 composite ceramics with high relative densities have been fabricated by hot pressing of a mixture of hexagonal boron...
1426
Authors: Y. Xiong, Zheng Yi Fu, Hang Wang
Abstract:Translucent AlN ceramics were fabricated using spark plasma sintering (SPS) technique with 3wt% CaF2 as sintering additive. The samples...
545
Authors: Toyohiko Yano, Junichi Yamane, Katsumi Yoshida
Abstract:For the transmutation of the very long half-lived isotopes which are separated from the spent nuclear fuels, it is necessary to find proper...
23
Authors: Daisuke Horikawa, Junichi Tatami, Toru Wakihara, Katsutoshi Komeya, Takeshi Meguro
Abstract:HfO2-added Si3N4 ceramics are known to exhibit excellent high-temperature strength and excellent damage characteristics because HfO2 assists...
35
Authors: Xiao Lei Li, Li Ying Wang, Er An Zai, Hong An Ma, Xiao Peng Jia
Abstract:Heat treatment is an effective means of structural adjustment and performance improvement of AlN ceramics. AlN ceramics prepared at high...
68