Silicon/phenolic hybrid resins are one of the most commonly used materials for thermal protection. However, the weak ability of SiO generated by silicone during ablation to resist the impact of high-speed hot gas flow hinders further improvement of the performance. Therefore, in this work, the ultrahigh-temperature ceramic elements Zr and Hf were integrated into hyperbranched polysiloxanes in the form of coordination bond and then introduced into phenolic resin (PR), obtaining hybrid resin with excellent ablative resistance. During ablation, Zr and Hf will first undergo ceramization, producing ZrO and HfO. Subsequently, they will undergo a solid solution sintering reaction to produce complex-phase ceramic particles (ZrHf)O, which are embedded in the SiO liquid film and provide excellent pinning effect. This gives the hybrid resin excellent ablation resistance, whose linear ablation rate can be as low as 0.038 mm/s, a 58 % decrease compared to pure PR. This work not only provides a new pathway for ceramization through metal ion coordination bonding, but also provides a new way to prepare high-performance TPS materials.

中文翻译：

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聚硅氧烷中配位 Zr4+ 和 Hf4+ 的陶瓷化赋予有机硅/酚醛混合树脂优异的热防护性能


硅/酚醛混合树脂是最常用的热防护材料之一。然而，有机硅在烧蚀过程中生成的SiO抵抗高速热气流冲击的能力较弱，阻碍了性能的进一步提高。因此，本工作将超高温陶瓷元素Zr和Hf以配位键的形式整合到超支化聚硅氧烷中，然后引入酚醛树脂（PR）中，得到具有优异耐烧蚀性能的杂化树脂。烧蚀过程中，Zr和Hf首先发生陶瓷化，产生ZrO和HfO。随后，它们将发生固溶烧结反应，生成复相陶瓷颗粒(ZrHf)O，该颗粒嵌入SiO液膜中并提供优异的钉扎效果。这使得杂化树脂具有优异的耐烧蚀性能，其线性烧蚀速率可低至0.038毫米/秒，比纯PR降低了58%。该工作不仅为金属离子配位键合陶瓷化提供了新途径，也为制备高性能TPS材料提供了新途径。