Free standing graphene/SiC films by in-situ carbothermal reaction as thermal shielding materials

• Free-standing Graphene/SiC film was prepared by one step in-situ carbothermal reaction with graphene oxide/Si film as precursor.
• Graphene/SiC film shows the best anti-ablation performance and mechanical properties when the weight ratio of graphene oxide and Si is 3:1.
• In-plane and out of plane thermal conductivity of graphene/SiC film are 27.98 Wm−1 K−1 and 0.15–0.23 Wm−1 K−1, respectively.
• After removing graphene layer, hardness and elastic modulus of Graphene/SiC film were reduced to from 0.56 Gpa to 0.001 Gpa and from 3.40 Gpa to 0.043 Gpa, respectively.

Effective thermal shielding materials with perfect anti-ablation and mechanical performances play a pivotal role of protecting aircraft suffering harsh conditions. With graphene oxide (GO) and nano-silicon spheres as raw material, a layered Si/GO precursor film was prepared by filtration, followed by in-situ carbothermal reaction to obtain the composite film of SiC and graphene (SiC/G film). The as-obtained material shows a sandwich-like anisotropic structure, with excellent anti-ablation performance in ablation experiment. The film exhibit a high mechanical stiffness with hardness and elastic modulus of 0.56 and 3.40 GPa, respectively. Besides, in- and out-plane thermal conductivity are 27.98 and 0.15–0.23 Wm− 1 K− 1, respectively. In the film, the orientated graphene sheets are not only the scaffold to retain the integrity of the film, but also improve in-plane thermal dissipation efficiency. Meanwhile, in-situ grown SiC particles act as the major anti-ablation functional layer, as well as the interlayer spacer to retard the heat transfer perpendicular to the film. Therefore, this novel sandwich-like structure composed by SiC and graphene layers could offer great protection from multiple ablation shocks in many fields.

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