自然科学版 英文版
自然科学版 英文版
自然科学版 英文版

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中南大学学报(英文版)

Journal of Central South University

Vol. 27    No. 9    September 2020

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Fabrication and flexural strength of porous Si3N4 ceramics with Li2CO3 and Y2O3 as sintering additives
HU Hai-long(胡海龙)1, 2, LUO Shi-bin(罗世彬)1

1. School of Aeronautics and Astronautics, Central South University, Changsha 410083, China;
2. Research Center in Intelligent Thermal Structures for Aerospace, Central South University,
Changsha 410083, China

Abstract:By employing sintering additives of Li2CO3 and Y2O3, porous Si3N4 ceramics are prepared after experiencing the processes of sintering and post-vacuum heat treatment at 1680 and 1550 °C, respectively. The experimental results demonstrate the completed phase transformation from α to β-Si3N4 in Si3N4 ceramic samples with a amount of 1.60 wt% Li2CO3 (0.65 wt% Li2O) and 0.33 wt% Y2O3 additives. The as-synthesized porous Si3N4 ceramics exhibit high flexural strength ((126.7±2.7) MPa) and high open porosity of 50.4% at elevated temperature (1200 °C). These results are attributed to the significant role of added Li2CO3 as sintering additive, where the volatilization of intergranular glassy phase occurs during sintering process. Therefore, porous Si3N4 ceramics with desired mechanical property prepared by altering the addition of sintering additives demonstrate their great potential as a promising candidate for high temperature applications.

 

Key words: sintering additive; flexural strength; porosity; glassy phase; Si3N4 porous ceramics

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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