What are the excellent properties of expanded graphite
1.1 High compressibility and resilience: for expanded graphite products, there are still many closed small open spaces that can be tightened under the action of external force. At the same time, they have resilience due to the tension of the air in the small open spaces.
1.2 Flexibility: the hardness is very low. It can be cut with ordinary tools, and can be wound and bent arbitrarily;
2、 Physical and chemical functions:
2.1 Purity: the fixed carbon content is about 98%, or even more than 99%, which is enough to meet the requirements of high-purity seals in energy and other industry;
2. Density: the bulk density of flake graphite is 1.08g/cm3, the bulk density of expanded graphite is 0.002 ~ 0.005g/cm3, and the product density is 0.8 ~ 1.8g/cm3. Therefore, the expanded graphite material is light and plastic;
3. Temperature resistance: theoretically, the expanded graphite can withstand – 200 ℃ to 3000 ℃. As a packing seal, it can be safely used at – 200 ℃ ~ 800 ℃. It has the excellent functions of no embrittlement, no aging at low temperature, no softening, no deformation and no decomposition at high temperature;
4. Corrosion resistance: it has chemical laziness. In addition to some specific temperatures of strong oxidants such as aqua regia, nitric acid, sulfuric acid and halogen, it can be used to most media such as acid, alkali, salt solution, seawater, steam and organic solvent;
5. Excellent thermal conductivity and small thermal expansion coefficient. Its parameters are close to the same order of magnitude of the dual part data of general sealing equipment. It can also be well sealed under the working conditions of high temperature, cryogenic and sharp temperature change;
6. Radiation resistance: subject to neutron rays γ Ray α Ray β X-ray irradiation for a long time without obvious change;
7. Impermeability: good impermeability to gas and liquid. Due to the large surface energy of expanded graphite, it is easy to form a very thin gas film or liquid film to hinder the medium penetration;
8. Self lubrication: the expanded graphite still maintains the hexagonal plane layered structure. Under the action of external force, the plane layers are easy to slide relatively and self lubrication occurs, which can effectively prevent the wear of shaft or valve rod.
Post time: Sep-02-2021