Novel High-Temperature-Resistant Phosphates: Thermal Ablation Behavior of La–Al System Phosphates at 2000 °C

[Image: see text] The saturation-free and directionless cross-linking and interpenetration processes between La(3+) and [(H(2)PO(4))2Al(HPO(4))]-plasma in La–Al phosphate by mixing Al(OH)(3), CrO(3), and H(2)O(2) dissolved in H(3)PO(4) and La(2)O(3) as a curing accelerator, as well as the thermal stability of the La–Al phosphate bulk materials and the evolutions of the phase composition and morphology at different temperatures were studied using thermogravimetric/differential scanning calorimetry under different temperatures in a muffle furnace. The La–Al phosphates showed good thermal stability, and the thermal weight loss rate of the materials decreased from 18% before heat treatment to ∼2% after heat treatment. In addition, the La–Al phosphate bulk material showed excellent resistance to ablation when subjected to ablation by an oxyacetylene flame at 2000 °C for 30 s. It evolved into a dense LaPO(4) and AlPO(4) high-temperature phase layer on the sample surface, which prevented further ablation damage to the sample and significantly improved the temperature resistance of the La–Al phosphate bulk material.