The sealing material can be prepared into a liquid or paste form during use, applied between the contact surfaces of two components, and cured or formed as non drying putty under certain conditions to serve as a sealing effect; It can also be processed into solid or hollow rings of various shapes and installed between the contact surfaces of two components to provide a sealing effect. The former refers to sealing materials only used for static sealing parts where there is no relative movement between the contact surfaces of two components; The latter refers to seals that can be used not only for static sealing parts, but also for dynamic sealing parts where the contact surfaces of two components have relative motion.
The main sealing materials used in the aerospace industry are polysulfide rubber, silicone rubber and polyurethane sealant. Polysulfide rubber sealant has excellent performance of resistance to aviation fuel, and is mainly used for sealing the integral fuel tank of wings and fuselage. Silicone rubber sealant can withstand high and low temperatures, radiation, vacuum, pollution-free, and non-toxic, and is mainly used for sealing various sealed cabins. Polyurethane sealant has good low-temperature performance and is mainly used for connecting seams of liquid hydrogen and liquid oxygen in rocket propellants. Sealants are also used for the sealing of aircraft cabins, window doors, instrument compartments, shell compartments, ejectors, electrical plugs, electronic components, and electromagnets.
The sealing material includes metal materials (aluminum, lead, indium, stainless steel, etc.), non-metallic materials (rubber, plastic, ceramics, graphite, etc.), and composite materials (such as rubber asbestos board), but rubber based elastomeric materials are more commonly used.