Zirconium phosphate ceramic composites: High-temperature resistant materials for thermal protection and insulation up to 2500℃

The development of new ablation-resistant and heat-insulating integrated materials for thermal protection of hypersonic vehicles is extremely important, but significant challenges remain. In this study, zirconium-based phosphate ceramics were developed by mixing a nano powder of the traditional ultra-high temperature ceramic oxidation product ZrO₂, which has excellent thermal insulation performance, with an aluminum–chromium phosphate slurry, which provides a certain degree of thermal stability. The zirconium-based phosphate ceramics crosslinked and cured by a polycondensation reaction inherited the high temperature resistance of ZrO₂ and the low thermal conductivity of the phosphate material, and simultaneously achieving excellent thermal stability, mechanical properties, and the desired properties. The mass ablation rate and line ablation rate of the zirconium-based phosphate ceramics were found to be 0.0173 g/s and 0.0114 mm/s, respectively, under oxyacetylene flame ablation at 2527℃ for 30 s. In addition, cooling by up to 2301℃ was achieved over a distance of 10 mm in the thickness direction was achieved. The zirconium-based phosphate ceramics also exhibited remarkable compressive strength (6.23–29.22 MPa), good thermal insulation (0.827–1.784 W/m·K), excellent thermal stability, and mass loss within 2.2 % in thermogravimetric tests from room temperature to 1400 ℃. These properties indicate that zirconium-based phosphate ceramics can be utilized in thermal protection systems in hypersonic vehicles, rocket propulsion, and missile launchers.