Dissociated oxygen environments are typically encountered during the hyper-speed flight of vehicles. Silicon carbide (SiC) is a typical material used in the thermal protection systems of hyper-speed vehicles; therefore, its oxidation behavior under dissociated oxygen conditions is crucial to the safety of flights. In this study, a high-frequency plasma wind tunnel was used to generate the dissociated oxygen environments to investigate the oxidation behavior of SiC in such environments. During the experiments, growth of silica (SiO2) was observed on the surface; however, the thickness of this oxide layer reduced simultaneously. A para-linear curve was used to fit the experimental data to distinguish between the growth and recession processes. By combining molecular dynamics simulations with aerodynamic calculations, it was found that the oxidation of SiC was governed by the diffusion of dissociated oxygen through the channels in the SiO2 crystal, while the loss of surface SiO2 was due to its sublimation. These findings establish a theoretical foundation for determining the failure boundaries of SiC materials during hyper-speed flight.

中文翻译：

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SiC 在解离氧环境中的氧化行为


在飞行器的超高速飞行过程中，通常会遇到解离氧环境。碳化硅 （SiC） 是用于超高速车辆热保护系统的典型材料;因此，它在解离氧条件下的氧化行为对飞行安全至关重要。在这项研究中，使用高频等离子体风洞来产生解离氧环境，以研究 SiC 在此类环境中的氧化行为。在实验过程中，观察到二氧化硅 （SiO2） 在表面生长;然而，该氧化层的厚度同时减小。使用平行线性曲线拟合实验数据，以区分增长和衰退过程。通过将分子动力学模拟与空气动力学计算相结合，发现 SiC 的氧化是由解离氧通过 SiO2 晶体中通道的扩散控制的，而表面 SiO2 的损失是由于其升华。这些发现为确定 SiC 材料在超高速飞行过程中的失效边界奠定了理论基础。