Ablation Capability of Flake Graphite Reinforced Barium-phenolic Resin Composite under Long Pulse Laser Irradiation

The carbon fiber reinforced phenolic resin composite is widely used as a thermal protection material because of its excellent thermal ablation. A novel flake graphite reinforced barium-phenolic resin composite was made by roller coating technology and its thermal ablation capability under long pulse laser irradiation was studied. The results show that the thermal ablation rate of the flake graphite reinforced barium-resin composite is 32.8 μg/J at 1700 W/cm 2 irradiation power density, which is much lower than that of the carbon fiber reinforced barium-resin composite or barium-phenolic resin obviously. The anti-ablative mechanism of the flake graphite reinforced barium- phenolic resin composite is investigated by the observation of its microstructure and the calculation of the laser en- ergy coupling with the material. It is found that the flake graphite is arrayed homogeneous alignment as sandwich among the composite. When the laser radiation gets on the composite, the flake graphite plays as a mirror and re- flects part of the laser, and then the laser radiation energy deposition on the composite is reduced. It is also found that the size of the flake graphite also affects the ablation capability. The composite with the flake graphite diameter of about 0.5 mm has the lowest thermal ablation rate.