Preparation of ablative resistance CF-ZrO₂ gradient composites by the pressure-assisted osmosis method

The ablative resistance composites with gradient structures are potentially applied to the protection on the outer wall of a solid rocket engine nozzle. We successfully prepared the ablative-resistant ZrO2-doped carbon fiber (CFZrO2) composite with the gradient structure via pressure-assisted osmosis. We analyzed the interception efficiency of ZrO2 particles per layer in the gradient structure and the ablative resistance mechanism of the composite using CFD-DEM simulations and experiments. The results indicate that the surface density of carbon cloth and the properties of fluid phase, including ZrO2 particle size, solid content, kinematic viscosity and flow rate can significantly affect the distribution of ZrO2 particles and mass interception efficiency per layer in the gradient composite. Importantly, we successfully prepared an optimal CF-ZrO2 gradient composite that exhibited a decrease in the mass ablation rate by 0.125 mg/s compared to the undoped CF composite. This is primarily due to the presence of dense and molten layers of ZrO2 particles embedded in the composite, resulting in the excellent ablative resistance performance of the functional gradient composite.