浙江大学高超课题组《AFM》：高导热性且结构稳定的石墨烯/陶瓷纤维，用于飞行器热防护系统、火箭喷嘴等

成果简介

碳纤维（CF）在制备适用于极端高温环境的隔热材料方面具有广阔前景。然而，由碳纤维与陶瓷涂层组成的典型隔热材料性能仍不尽如人意，主要原因在于其导热系数偏低且界面稳定性较弱。本文，浙江大学高超课题组《ADVANCED FUNCTIONAL MATERIALS》期刊发表名为“Highly Thermally Conductive yet Structurally Stable Graphene/Ceramic Fiber for Extreme Thermal Protection”的论文，研究以导热系数约1200 W m−1 K−1的石墨烯纤维（GF）为起点，通过一步熔盐合成法，成功制备出具有明确核壳结构的高导热性、高结构稳定性石墨烯/碳化钛纤维（GTF）。

当壳层厚度优化至1微米时，单根GTF展现出745 W m⁻¹ K⁻¹的导热系数及优异的抗热冲击性能，界面无失效现象，确保其在极端条件下长期服役的耐久性。此外，GTF编织体表现出卓越的抗烧蚀能力，经2200°C氧氢火焰暴露后，质量烧蚀率仅为0.3 mg s⁻¹。其卓越性能源于：玻璃纤维固有的高导热性实现快速热量散逸，玻璃纤维与碳化物涂层间形成的全尺度分形状互锁界面有效承载局部界面应力。本研究为玻璃纤维/陶瓷复合材料作为新一代疏浚工程热防护材料铺平道路，可满足极端热流管理与结构完整性需求。

图文导读

图1、(a), (b) Schematic of the preparation process of conventional CTF (a) and GTF with full-scale fractal-like interlocking interfaces (b) via MSS. (c) Digital photo of GTW (scale bar: 5 mm). (d) Infrared image of GTW captured during the ablation test (scale bar: 5 mm). (e) Schematic of the heat dissipation during the ablation test. (f) Comparison of the overall performance of GTF and CTF.

图2、Preparation and structural characterization of GTF. (a) Schematic illustration of the MSS method. (b) SEM images of GTF and corresponding elemental mapping images of C and Ti (scale bar: 5 µm). (c–f) Surface roughness (c), XRD patterns (d), Raman spectra (e), and XPS C1s and Ti2p spectra (f) of GTF.

图3、Microstructure evolution of TiC coating on GF. (a) SEM images of the steps to form the TiC coating and the corresponding schematic illustration. (b) XRD patterns of GTF prepared at varied temperatures. (c), (d) Sintering temperature-dependent TiC crystallite size (c) and coating thickness (d). (e), (f) XRD patterns of GTF prepared at 950°C (e) and 750°C (f). (g) Relationship of TiC crystallite size with sintering time at 950°C and 750°C. (h) Comparison of the D_eff between GTF and CTF. (i) Schematic illustration of TiC coating evolution. Activation energy for nucleation is usually higher than that for crystal growth. Raising the temperature, due to the increased nucleation rate, spatial confinement, and enhanced diffusion, the growth rate of the crystallite size slows down, while the coating thickness significantly goes up.

图4、Thermal conductivity and interface structure of GTF. (a) Thermal conductivity of GTF with different TiC coating thickness (GTF-x, x: coating thickness, unit: µm). (b), (c) Effect of flame shock duration (b) and liquid nitrogen shock time (c) on the thermal conductivity of GTF. (d–g) Schematic illustration and corresponding SEM image of the GF/TiC interlocking interfaces at micro-scale (d), (e), and nanoscale (f), (g). (h), (i) Schematic illustration and corresponding HRTEM image of the GF/TiC interlocking interface at atom-scale and corresponding elemental mapping images. (j) HRTEM image of GF/TiC interface. (k) EELS recorded from three different positions marked in j. (l) Local lattice strain distribution of the GF/TiC interface. (m) Raman mapping of the G peak of GTF. The red-shift of the G-band indicates the presence of tensile strain at the core-shell interface.

图5、Ablation resistance behavior of GTW. (a) Photo of GTW during ablation test. (b) The MAR of GTW and CTW at various ablation times. (c) Photos and corresponding SEM image of the backside of GTW and CTW after ablation test. (d) Infrared images of GTW captured during ablation test (scale bar: 5 mm). (e) Temperature profile of GTW and CTW along the horizontal direction after ablated for 90 s (The insert illustrates the temperature distribution, and the arrow indicates the range of temperature reading). (f) Temperature difference between the front and back sides of GTW and CTW at various ablation times. (g) Vertical thermal conductivity (k_⊥) of GTW and CTW from 25°C to 1000°C. (h) Schematic diagram of the heat dissipation process.

小结

我们提出一种全尺寸分形式互锁界面工程技术，用于构建具有卓越热防护与抗烧蚀性能的GTF复合材料，以满足疏浚工程热防护需求。当TiC壳层厚度优化至1微米时，单层GTF实现745 W m⁻¹ K⁻¹的导热系数，并在严苛的温度冲击循环中展现出优异的结构稳定性和性能稳定性。在2200°C氧氢火焰测试中，基于GTF的编织结构展现出0.3 mg s⁻¹的超低质量烧蚀速率，通过协同高效的平面内热扩散与快速层间热传导，性能超越传统CF/TiC复合材料。GTF的全尺度分形状互锁界面使TiC层在高温烧蚀条件下保持结构稳定性。这些发现凸显了基体材料固有特性与界面工程在提升抗烧蚀性能中的关键作用。本研究确立了面向极端热-力-氧化耦合环境的下一代航空复合材料界面设计策略。GTF材料的卓越性能使其在高超速飞行器热防护系统、火箭喷嘴等关键应用领域展现巨大潜力，有效解决了热流管理与结构完整性并存的挑战。

文献：https://doi.org/10.1002/adfm.202524632