We know PTFE(Teflon) is a kind of coated of fastener，we could put it on threaded rods .Why ? what advantages of it ?In order to get the clear of the question ,we need to know what is Teflon？
"Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938. Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine.” from Wikipedia
High temperatures, corrosion resistance, chemical resistance
High Cost，expensive
