Journal of Inorganic Materials

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Preparation and Dielectric Properties of In Situ Reaction Bonded Porous Si3N4 Ceramics

XIA Yong-Feng1,2, ZENG Yu-Ping1, JIANG Dong-Liang1   

  1. 1. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China; 2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
  • Received:2007-09-20 Revised:2007-12-24 Online:2008-07-20 Published:2008-07-20
  • Contact: ZENG Yu-Ping E-mail:yuping-zeng@mail.sic.ac.cn

Abstract: Porous Si3N4 ceramics were prepared by in situ reaction-bonding technology, using Si3N4 and Al2O3 as starting materials. The effects of sintering temperature and holding time on their porosities, flexural strength, and dielectric properties were studied. The strength and dielectric constants of samples are improved with increasing of sintering temperature and holding time; but the result is reverse in the condition of sintering temperature >1350℃ and holding time >4h. The phase analyses results indicate that the porous Si3N4 ceramics are mainly composed of α-Si3N4, oxidated SiO2 (cristobalite) and Al2O3. Porous Si3N4 ceramics with porosities from 25.34% to 43.92% and flexural strength from 42.54 to 127.85MPa are obtained. Their dielectric constants are in the range from 3.3 to 4.6 and dielectric loss is about 0.005.

Key words: porous Si3N4 ceramics, dielectric properties, in situ reaction bonding, porosity

CLC Number: 

  • TQ174