Expandable graphite is also called flexible graphite. It uses graphite as raw material and undergoes special chemical treatment to form interlayer compounds. After high temperature treatment, it rapidly decomposes and expands again. The volume can be increased to several hundred times. It is called expanded graphite, loose Porous, flexible, wide temperature range, between 200-3600℃. It can withstand the long-term irradiation of neutrons, Y-, β- and other rays, and work under high temperature, high pressure or radiation conditions, without decomposition, deformation or aging, and stable chemical properties.