Effect of Graphene on Microstructure and Mechanical Properties of Si3N4/SiC Ceramics

Hailing Yang,1

Qinggang Li,1,*Email

Zhi Wang,2

Hao Wu,2

Yuying Wu,3

Pengkun Hou, 1

Xin Cheng1

1Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, Jinan 250022, China

2School of Material Science and Engineering, University of Jinan, Jinan 250022, China

3Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, 17923 Jingshi Road, Jinan 250061, China

Abstract

Graphene with 0.3% content was added to enhance the fracture toughness of Si3N4/SiC ceramics prepared by pressureless sintering. The microstructure, mechanical properties and toughening mechanism of ceramics were investigated. Results showed that the fracture strength significantly increased from 329.11 MPa to 443.19 MPa after adding graphene. The main toughening mechanism of ceramics was crack deflection since the existence of graphene platelets. The main phase compositions of samples were β-Si3N4 with a high aspect ratio and SiC located in the grain boundary, and the SiC particles could avoid the excessive growth of β-Si3N4 to reduce the strength.

Effect of Graphene on Microstructure and Mechanical Properties of Si3N4/SiC Ceramics