Oxidation behaviors of carbon fiber reinforced multilayer SiC-Si3N4 matrix composites

Laifei Cheng,Xiaomeng Fan,Tong Guo,Donglin Zhao,Jimei Xue,Fang Ye,Xiaolin Dang,Yongsheng Liu

doi:10.1007/s40145-021-0539-1

Abstract

Oxidation behaviors of carbon fiber reinforced SiC matrix composites (C/SiC) are one of the most noteworthy properties. For C/SiC, the oxidation behavior was controlled by matrix microcracks caused by the mismatch of coefficients of thermal expansion (CTEs) and elastic modulus between carbon fiber and SiC matrix. In order to improve the oxidation resistance, multilayer SiC-Si3N4 matrices were fabricated by chemical vapor infiltration (CVI) to alleviate the above two kinds of mismatch and change the local stress distribution. For the oxidation of C/SiC with multilayer matrices, matrix microcracks would be deflected at the transition layer between different layers of multilayer SiC-Si3N4 matrix to lengthen the oxygen diffusion channels, thereby improving the oxidation resistance of C/SiC, especially at 800 and 1000 °C. The strength retention ratio was increased from 61.9% (C/SiC-SiC/SiC) to 75.7% (C/SiC-Si3N4/SiC/SiC) and 67.8% (C/SiC-SiC/Si3N4/SiC) after oxidation at 800 °C for 10 h.

Highlights

Carbon fiber reinforced SiC matrix composites (C/SiC) have been considered as a kind of promising hightemperature structural material [1,2,3]
The Si3N4 matrix cannot be detected by X-ray diffraction (XRD)
Multilayer SiC–Si3N4 matrices were introduced into carbon fiber reinforced SiC matrix composites (C/SiC) by chemical vapor infiltration (CVI) process, and the oxidation behaviors of the as-prepared composites were www.springer.com/journal/40145

Summary

Introduction

Carbon fiber reinforced SiC matrix composites (C/SiC) have been considered as a kind of promising hightemperature structural material [1,2,3]. They have great application potential in aero-engines, aircraft/high-speed train braking systems, and aerospace aircraft thermal protection systems due to the low density, excellent. One way to improve the oxidation resistance of C/SiC is to reduce the CTEs and elastic modulus mismatch between the carbon fiber and the SiC matrix. Si3N4 is a kind of noteworthy oxidation-resistant ceramic, and its CTEs and elastic modulus are generally higher than those of carbon fiber, but lower than those of SiC [7,14,15,16,17,18,19]. The evolutions of microstructure and mechanical properties in the oxidation process were revealed

Experimental

Results and discussion

Conclusions