Dry lubricants do not use a liquid media, but are able to provide lubrication while remaining in a solid state. Also called solid lubricants, dry lubricants can have high oxidative and thermal degradation resistance. Some advantages that dry lubricants provide include the ability to perform at extreme temperatures that would cause liquids to evaporate or freeze as well as clean operation because dirt and debris will not stick to solids like they would to liquids such as oil or grease.Able to act as both a lubricant and a sealant, dry lubricants are often used in applications such as slide mechanisms, air compressors, railway track joints, space vehicles, catheters, bearings, circuit boards and transducers. Often referred to as a film or coating, dry lubricants bond to the surface of the machine or part and, as a result, offer a longer wear life than liquid lubricants, such as lubricating oil, which can be difficult to apply and retain. Lubricating oils do have their advantages though, including the fluidity to be stored in a system and replenish a supply automatically, such as oil within cars. Typical industries that benefit from the use of dry lubricants include aerospace, electronics, automotive, medical, petrochemical, industrial, food processing and agricultural. Dry lubricants consist of four common materials, which are hexagonal boron nitride, graphite, molybdenum disulfide, PTFE and other less common, materials such as tungsten disulfide, talc, calcium fluoride, silicone and cerium fluoride.