For many gasket materials, applications involving high temperatures are challenging. Non-graphite gasket materials, such as nitrile rubber, silica gel, polytetrafluoroethylene, etc., can only withstand a certain level of temperature. For example, the application temperature of nitrile rubber gaskets can reach up to 95°C, while the application temperatures of silicone and PTFE can reach up to 200°C and 260°C, respectively. For applications with temperatures above these temperatures, graphite gaskets are the first choice.
Graphite is a kind of carbon and an inert material that can resist chemical attack even at high temperatures. Because it is an inert material, it is unlikely to react with or contaminate other substances. The graphite sheets used in the production of gaskets can withstand high temperatures. Typical temperature ranges include oxidizing atmospheres from -240°C to 510°C and pressures up to 2000 psi. High-purity graphite flakes can become brittle, therefore, high-purity graphite flakes are usually reinforced with metal core inserts to provide additional strength and stability.
Flexible graphite gaskets have excellent corrosion resistance to various acids, alkalis and salt solutions, organic compounds and heat transfer fluids, even in high temperature applications. Washers cut from flexible graphite sheets are an excellent choice for harsh conditions in general industrial, petrochemical, pulp and paper, mining and chemical applications. The flexible graphite board is made of mineral graphite (expandable flake graphite) with a carbon content of 95% to 99%. The amount of carbon present in a sheet is a key determinant of its flexibility: the higher the percentage of carbon present, the more flexible the sheet. Flexible graphite gaskets have excellent resistance to corrosive chemicals, high temperature and high pressure. These characteristics make flexible graphite gaskets an ideal choice for severe applications. In addition, flexible graphite gaskets have good resistance to abrasive media, while also having excellent thermal conductivity and material consistency, so as to achieve excellent sealing.