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Fabrication of electrically conductive barium aluminum silicate/silicon nitride composites with enhanced strength and toughness Qiang Liu1,*, Yang Wang1, Zhu-Qing Gao1, Biao Zhang1, Zhao-Ping Hou2, Hai-Jiao Zhang1, Feng Ye1,* , and Wen Wang1 1

Institute for Advanced Ceramics, Key Laboratory of Advanced Structural-Functional Integration Materials and Green Manufacturing Technology, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China 2 College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China

Received: 12 July 2020

ABSTRACT

Accepted: 29 September 2020

To acquire Si3N4-based composite with combination of high mechanical properties and excellent electrical conductivity, dense multi-walled carbon nanotubes (MWCNTs)-dispersed Si3N4 ceramics were fabricated, using BaCO3– Al2O3–SiO2 (BAS) as a second phase to improve the density and avoid reaction between MWCNTs and Si3N4. The results revealed that 40 wt% BAS prominently benefited the densification of MWCNTs-dispersed Si3N4 composites and promoted the phase transformation of a-Si3N4 to b-Si3N4, thereby contributing to superior mechanical properties. Additionally, the effects of MWCNTs on the densification, phase transformation, microstructure and properties were investigated. MWCNTs were well dispersed without damage in BAS/Si3N4 composites exhibiting excellent electrical conductivity. Consequently, these composites would be expanded to more applications including electrostatic chargeless bearing and electromagnetic interference shielding as well as hightemperature structural applications with geometrically complex morphologies.

Published online: 12 October 2020

Ó

Springer Science+Business

Media, LLC, part of Springer Nature 2020

Introduction Silicon nitride (Si3N4) ceramic is one of the most promising materials for high-temperature structural applications due to its excellent high-temperature

strength, high creep resistance and good resistance to oxidation, thermal shock as well as chemical attacks [1, 2]. Furthermore, some applications are in space shuttle engines bearings and apparatus for semiconductor processes where high rotation speed and high accuracy are needed. However, the high insulation of

Handling Editor: Shen Dillon. Qiang Liu and Yang Wang have contributed equally.

Address correspondence to E-mail: [email protected]; [email protected]

https://doi.org/10.1007/s10853-020-05409-5

1222 Si3N4 ceramics can make the system break down because they will cause static electricity stimulating fine particles and dusts to adhere on the surfaces. Therefore, fabricating highly electrical conductive silicon nitride-based composites can enlarge their applications within electromagnetic interference (EMI) shielding that work in harsh environment such as oxidizing and high temperature [3]. At present, many efforts have been developed to fabricate electrically conductive Si3N4 ceramics. One notable example is adding a high electrical conductive second phase into Si3N4-base