Anisotropy in thermal properties of boron carbide–graphene platelet composites

Dense boron carbide–graphene composites were prepared by hot-pressing method. Phase analysis revealed presence of small amount of tungsten borides contamination in all sinters. Microstructure of composites showed orientation of graphene platelets. The anisotropy of wave velocity in ultrasonic measurements reached 25%. The values of thermal diffusivity and thermal conductivity were determined in different directions using laser flash analysis methods (LFA 427). For the composite containing 4 wt% of graphene platelets the anisotropy of thermal properties exceed 70%. Boron carbide–graphene composites were also examined in the field of thermal stability in air using DTA-TG apparatus. Oxidation of boron carbide started above 720 °C. Boron oxide layer formed on the surface was observed under scanning electron microscope.