In order to prepare the high-quality graphene and promote its application in the metal radiator, the heat dissipation efficiency of the metal radiator was improved.The graphene nanoparticles were prepared by a self-made jet cavitation device of supercritical CO2, which were further used to prepare the graphene composite coating with high heat dissipation, and the metal composite radiators with the graphene composite cooling coating on the surface were fabricated by spray coating method.Results showed that the graphene nanoparticles prepared by jet cavitation of supercritical CO2 had high purity, large lamellae and few layers, presenting good thermal conductivity.The graphene composite coating prepared with using the graphene nanoparticles could reduce the temperature of the original metal radiator by 16.13 ℃ and increased the heat dissipation efficiency of the metal radiators by 15.6%～21.6% at room temperature.
