Anti-ablation properties of ZrB₂ modified carbon/phenolic composites in plasma wind tunnel

Improving the ablative resistance of carbon/phenolic (C/Ph) composites is an urgent need in the field of thermal protection of hypersonic vehicles. In this paper, novel C/Ph composites are fabricated by introducing different contents of ZrB2 ceramic particles, and the anti-ablation properties of the composites are tested in plasma wind tunnel. Under mainstream conditions with enthalpy of 21.84 MJ/kg, heat flux of 1.6 MW/m(2), and pressure of 1.6 kPa, the effects of ZrB2 ceramic content on the thermal stability, linear ablation rate and surface temperature of C/Ph composites are further analyzed. The maximum ablative surface temperature is positively correlated with the content of ZrB2. As the ZrB2 content increases, the back face temperature of the materials decreases gradually, while the linear ablation rate increases slightly after a significant decrease. When the ablation time is 50 s, The linear ablation rate of the sample with 7% ZrB2 content is the lowest (0.0184 mm/s). These dates of the plasma wind tunnel test could provide a reference for applications of C/Ph composites. The oxidation of ZrB2 in the materials contributes significantly to improving its anti-ablation properties in severe environments. Accordingly, optimizing the ZrB2 content enables the development of high-performance C/Ph composites with enhanced thermal properties, and reduced ablation rates, making them well-suited for thermal protection applications.