Conventional aluminum nitride (AlN) whisker synthesis faces inherent limitations, including high reaction temperature, prolonged processing time, high cost and restricted whisker length. Herein, we proposed a novel self-generated reactor strategy that enables the efficient combustion synthesis of ultra-long AlN whiskers. This strategy was realized in the Al/NH₄Cl/PTFE system, where an eggshell-like reactor formed in-situ, establishing a thermodynamically stable and confined environment. This unique architecture was crucial for the controlled growth of uniform and high-aspect-ratio whiskers. Under optimized conditions (7% (in mass) NH₄Cl and PTFE/Al molar ratio of 0.015), AlN whiskers with an average diameter of 0.52 μm and a length exceeding 1 mm (aspect ratio >1900) were successfully obtained. Based on thermal reactivity and thermo-kinetic analyses, a possible mechanism for the formation of the self-generated reactor and the subsequent growth of ultra-long AlN whiskers within it was proposed. Furthermore, the synthesized whiskers were incorporated into nanofibrillated cellulose to fabricate composite films, which demonstrated a high in-plane thermal conductivity of 13.16 W·m⁻¹·K⁻¹. This work not only provides a novel and efficient pathway for AlN whiskers synthesis but also highlights their potential for practical thermal management applications.

Graphite materials are promising aerospace structural materials owing to their low density, high thermal conductivity, and high temperature stability. However, the poor mechanical properties and inferior ablation resistance of graphite materials limit their application in advanced space vehicles. To address this problem, three-dimensional zirconium carbide (3D ZrC) skeleton-reinforced graphite composites (mesocarbon microbeads, MCMBs) were designed and fabricated by combination of molten salt coating and spark plasma sintering (SPS). The effects of ZrC content on the mechanical and ablation properties were investigated in detail. With the ZrC content of 45 vol%, the bending strength and fracture toughness of the MCMB@ZrC composite were 112 MPa and 1.72 MPa·m^1/2, respectively. After ablation at 2.4 MW·m⁻² for 60 s, the MCMB@ZrC composites with 30 vol% ZrC exhibited the best ablation performance and remained intact after ablation, with linear and mass ablation rates of 2.13 μm·s⁻¹ and 4.24 mg·s⁻¹, respectively. The 3D ZrC skeleton with moderate content provides effective support for the graphite matrix and thermal protection during the ablation process to a certain extent.