White fuming nitric acid

White fuming nitric acid (WFNA) is a storable liquid oxidizer used with kerosene and hydrazine rocket fuel. It consists of nearly pure nitric acid (hydrogennitrogenoxygen₃). WFNA is commonly specified as containing no more than 2% water and less than 0.5% dissolved nitrogen dioxide or dinitrogen tetroxide.

WFNA was sometimes used with an inhibitor compound to reduce corrosiveness, often hydrogen fluoride. Without inhibitors, WFNA will corrode nearly all structural metals. Inhibited WFNA is often called IWFNA. The hydrogen fluoride addition causes formation of protective layer of fluoride on the metal surfaces.

WFNA as an oxidizer has somewhat less performance than red fuming nitric acid but is considerably safer (though extremely corrosive), as it has little to no dissolved nitrogen tetroxide, which is an extremely toxic and volatile chemical. If not inhibited, it will form nitrogen tetroxide on contact with most metal and some organic materials.

WFNA and IWFNA are considered hypergolic with a long list of other propellants, including:
* UDMH
* Hydrazine
* Furfuryl alcohol
* Gasoline
* Aniline

External links

* [http://www.npi.gov.au/database/substance-info/profiles/65.html National Pollutant Inventory - Nitric Acid Fact Sheet]