Effect of SiBCN content on the dielectric and EMW absorbing properties of SiBCN-Si3N4 composite ceramics

Mingxi Zhao, Yongsheng Liu, Nan Chai, Hailong Qin, Xiaofei Liu, Fang Ye, Laifei Cheng, Litong Zhang

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

Siliconboron carbonitride ceramics (SiBCN) were introduced into porous Si3N4 substrates via low pressure chemical vapor deposition and infiltration from SiCl3CH3-NH3-BCl3-H2-Ar system. To improve the electromagnetic wave(EMW) absorbing properties, the molar ratio, nCH3SiCl3/(nNH3 + nBCl3), was increased based on thermodynamics analysis. The results show that nanosized silicon carbide crystals and free carbon dispersed uniformly in the amorphous SiBCN phase, resulting in suitable dielectric properties and improved absorption capabilities of SiBCN-Si3N4 ceramics. Additionally, with increasing SiBCN ceramics loading, the amount of nanocrystals and interface between nanocrystals and amorphous SiBCN phase increased, leading to enhanced polarization and dielectric loss of the composite ceramics. When SiBCN content was up to 3.64 wt%, the electromagnetic reflection coefficient (RC) of SiBCN-Si3N4 composite ceramics reached −40 dB (>99.97% absorbing) with the effective electromagnetic absorbing bandwidth of 3.64 GHz in the X-band. This study makes it possible to fabricate SiBCN-based composite materials with excellent EMW absorbing properties at a low temperature.

Original languageEnglish
Pages (from-to)1334-1340
Number of pages7
JournalJournal of the European Ceramic Society
Volume38
Issue number4
DOIs
StatePublished - Apr 2018

Keywords

  • Chemical vapor deposition and infiltration
  • Dielectric properties
  • Electromagnetic wave absorbing properties
  • Siliconboron carbonitride ceramics

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