Incorporating Metal Oxides to Significantly Improve the Ablative Performance of Silicone Rubber-Based Composites at 10% Tensile Strain Rate under Coupled Thermal-Mechanical-Oxidative Conditions

Abstract

Silicone rubber is able to provide excellent thermal protection and accommodates large deformation rates. However, the ablative properties of silicone rubber deteriorate significantly when it is subjected to ablation at large strain rates. To attempt to address the above problem, different types of metal oxides were adopted to enhance the ablative properties of vinyl methyl silicone rubber (VMQ), especially for enhancing the ablative performance at 10% tensile strain rate. The results revealed that the combined use of iron(II, III) oxide (Fe₃O₄) and zirconium dioxide (ZrO₂) was instrumental in improving the ablative properties of VMQ-based composites at 10% tensile strain rate and a heat flux of 1 MW/m². To further enhance the ablative performance, the ratio of Fe₃O₄ and ZrO₂ was optimized through an experimental design method. Results showed that when the ratio of Fe₃O₄ and ZrO₂ was 1.4:1, the maximum back-face temperature of a 3 mm thick silicone rubber composite remained below 200 °C, while the surface temperature was well above 2000 °C when it was stretched to a tensile strain rate of 10%. This work provides a reference for preparing high-performance flexible thermal ablative composites that exhibit promising application in aerospace and fire protection sectors, among others.