- 2 NH3 → 3 H2 + N2
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 heated in forming gas to drive out moisture and oxygen and to increase the base fog of the film. Hypersensitization is used particularly in deep-sky astrophotography, which deals with low-intensity incoming light, requires long exposure times, and is thus particularly sensitive to contaminants in the film.
Forming gas is also used to regenerate catalysts in glove boxes and as an atmosphere for annealing processes. It can be purchased at welding supply stores. It is sometimes used as a reducing agent for high-temperature soldering and brazing, to remove oxidation of the joint without the use of flux.
- "Forming gas specs" (PDF). Archived from the original (PDF) on July 14, 2011. Retrieved May 27, 2009.
- "Crystec Technology Trading GmbH, Ammonia cracker for the generation of forming gas". Retrieved April 19, 2009.
- Lodriguss, Jerry. "Gas hypersensitization". Catching the Light. Retrieved April 19, 2009.
- "Crystec Technology Trading GmbH, Thermal treatment of steel". Retrieved April 19, 2009.