Forming gas treatment of metals, because it reduces oxides on the metal surface. Forming gas Forming gas is a mixture of hydrogen (mole fraction varies) and nitrogen. It is sometimes called a "dissociated ammonia atmosphere" due to the reaction which generates it: It can also be manufactured by thermal cracking of ammonia, in an ammonia cracker or forming gas generator. Forming gas is used as an atmosphere for processes that need the properties of hydrogen gas. Typical forming gas formulations (5% H2 in N2) are not explosive. It is used in chambers for gas hypersensitization, a process in which photographic film is
Gas-operated reloading piston has traveled a short distance. Most systems, however, vent excess gas into the atmosphere through slots, holes, or ports. A gas trap system involves 'trapping' combustion gas as it leaves the muzzle. This gas impinges on a surface that converts the energy to motion that, in turn cycles the action of the firearm. Hiram Maxim patented a muzzle-cup system in 1884 described in though it is unknown if this firearm was ever prototyped. John Browning used gas trapped at the muzzle to operate a 'flapper' in the earliest prototype gas-operated firearm described in . The Danish Bang rifle used