High-purity graphite has the advantages of high strength, good thermal shock resistance, high temperature resistance, oxidation resistance, small resistivity, corrosion resistance, and easy precision machining. It is an ideal inorganic non-metallic material. It is used to process and produce electric heating elements, structural casting molds, crucible boats for smelting high-purity metals, heaters for single crystal furnaces, EDM graphite, sintering molds, electron tube anodes, metal coatings, graphite crucibles for semiconductor technology, emission electron tubes, thyristors, and graphite anodes and grids for mercury arc rectifiers, etc.
Special properties of high-purity graphite:
1. High temperature resistant type: The melting point of graphite is 3850±50℃, and the boiling point is 4250℃. Even after ultra-high temperature arc burning, the weight loss is very small, and the thermal expansion coefficient is also very small. The strength of graphite increases as the temperature increases. At 2000°C, the strength of graphite doubles.
2. Electrical conductivity and thermal conductivity: The electrical conductivity of graphite is one hundred times higher than that of ordinary non-metallic minerals. Thermal conductivity exceeds that of steel, iron, lead, and other metal materials. The thermal conductivity decreases as the temperature increases, and even at extremely high temperatures, graphite becomes a thermal insulator. Graphite can conduct electricity because each carbon atom in graphite only forms 3 covalent bonds with other carbon atoms, and each carbon atom still retains 1 free electron to transmit charge.
3. Lubricity: The lubrication performance of graphite depends on the size of graphite flakes. The larger the flakes, the smaller the friction coefficient and the better the lubrication performance.
4. Chemical stability: Graphite has good chemical stability at room temperature and is resistant to acid, alkali, and organic solvent corrosion.
5. Plasticity: Graphite has good toughness and can be rolled into very thin sheets.
6. Thermal shock resistance: When graphite is used at room temperature, it can withstand drastic changes in temperature without being damaged. When the temperature suddenly changes, the volume of graphite does not change much, and cracks will not occur.