Dynamic oxidation mechanism of carbon fiber reinforced SiC matrix composite in high-enthalpy and high-speed plasmas

Lingwei Yang,Liping Liu,Kai Jiang,Xinxing Han,Changhao Zhao,Jie Luo,Jun Zhang,Guolin Wang,Xueren Xiao

doi:10.1007/s40145-021-0540-8

Abstract

This work employed an inductively coupled plasma wind tunnel to study the dynamic oxidation mechanisms of carbon fiber reinforced SiC matrix composite (Cf/SiC) in high-enthalpy and high-speed plasmas. The results highlighted a transition of passive/active oxidations of SiC at 800–1600 °C and 1–5 kPa. Specially, the active oxidation led to the corrosion of the SiC coating and interruption of the SiO2 growth. The transition borders of active/passive oxidations were thus defined with respect to oxidation temperature and partial pressure of atomic O in the high-enthalpy and high-speed plasmas. In the transition and passive domains, the SiC dissipation was negligible. By multiple dynamic oxidations of Cf/SiC in the domains, the SiO2 thickness was not monotonously increased due to the competing mechanisms of passive oxidation of SiC and dissipation of SiO2. In addition, the mechanical properties of the SiC coating/matrix and the Cf/SiC were maintained after long-term dynamic oxidations, which suggested an excellent thermal stability of Cf/SiC serving in thermal protection systems (TPSs) of reusable hypersonic vehicles.

Highlights

The quest for higher Mach number and longer service time of hypersonic vehicles has advanced the development of novel thermal protection system (TPS) to resist severe aerodynamic heating
Passive and active oxidations of SiC are observed, and the latter is prone to occur at higher temperatures and lower partial pressures of O2 [16]
In high-enthalpy plasmas, the surface temperature is dependent on the thermal equilibrium between convection, conduction, radiation, chemical heating, etc., based on Eq (2): qtra,g qrad,g qchem,g qcon,l qrad,l where qtra,g and qrad,g are the heat gained by transfer and radiation from the heating flows, respectively [24]

Summary

Introduction

The quest for higher Mach number and longer service time of hypersonic vehicles has advanced the development of novel thermal protection system (TPS) to resist severe aerodynamic heating. Previous studies show that the Cf/SiC with SiC coatings can resist ultrahigh temperatures up to ~1750 °C in re-entry environments of hypersonic vehicles [7,10,11]. Coupled plasma wind tunnel is the main ground facility to simulate re-entry environment by generating a high-power electromagnetic field to the inside air. Due to the diversities of the models or the experimental facilities employed, the obtained transition border varies, and very few is determined in on-ground simulated environments, i.e., high-enthalpy and highspeed plasmas [11,18,20]. This work contributes to study the dynamic oxidation behavior of SiC coatings on a typical Cf/SiC TPS employing a 1 MW inductively coupled plasma wind tunnel available at China Aerodynamics Research and Development Center (CARDC, China). The multiple plasma exposures were essential to ascertain the dynamic oxidation behavior and the thermomechanical stabilities of Cf/SiC, to shed light on potential applications of TPS in reusable hypersonic vehicles

Materials and experiments

Results and discussion

Conclusions