Ablation of C/SiC-HfC composite prepared by precursor infiltration and pyrolysis in plasma wind tunnel

Liuyang Duan,Yiguang Wang,Liping Liu,Lei Luo

doi:10.1007/s40145-020-0379-4

Abstract

Carbon fiber reinforced silicon carbide-hafnium carbide (C/SiC-HfC) composite was prepared by precursor infiltration and pyrolysis process. Then, ablation behavior of C/SiC-HfC was evaluated in plasma wind tunnel. It was found that oxide layer formed during ablation significantly influenced the surface temperature. Formation of dense HfO2-SiO2 layer under low heat flux led to stable surface temperature. Silica (SiO2) on the surface was gradually consumed when heat flux increased, resulting in conversion of HfO2-SiO2 on the surface to HfO2. Converted HfO2 with high catalytic coefficient absorbed more energy, causing gradual increase in the surface temperature. Formed oxide layer was destroyed at high heat flux and high stagnation point pressure. After carbon fiber lost the protection of HfO2-SiO2 layer, it burned immediately, leading to surface temperature jump.

Highlights

During the hypersonic flight of vehicles in the atmosphere, a large amount of heat is generated due to the friction between vehicles and the atmosphere, causing the surface temperature of the vehicles to exceed 2000 °C [1,2]
Carbon fiber reinforced silicon carbide (C/SiC)–HfC composite was successfully prepared by precursor infiltration and pyrolysis process
The ablation behavior of the C/SiC–HfC composite was studied in plasma wind tunnel

Summary

Introduction

During the hypersonic flight of vehicles in the atmosphere, a large amount of heat is generated due to the friction between vehicles and the atmosphere, causing the surface temperature of the vehicles to exceed 2000 °C [1,2]. HfC was often introduced into C/SiC composites as an ideal UHTC to form modified C/SiC–HfC composite. For the comparative analysis of the diffusion mechanism of different microstructures during ablation, HfC phase used for modification was introduced via precursor infiltration and pyrolysis (PIP) process in this study, because PIP process has advantages such as easy designability of microstructures, low preparation temperature, and high mechanical properties of final composite, and uniform distribution of modified UHTCs [23,24,25]. Pure plasma flow can avoid the influence of impurities in wind tunnel, such as copper in the arc wind tunnel, and it is highly desirable to study the ablation mechanism of C/SiC–HfC composite. Plasma wind tunnel was selected as the method for evaluating the ablation performance of C/SiC–HfC composite and investigating the diffusion mechanism of volatiles in this study. The ablation mechanisms of C/SiC–HfC composite in plasma wind tunnel were proposed

Experimental

Results and discussion

Conclusions