IRFNA = ..inhibited red fuming nitric acid"

Radiomic a) RP-1, JP-4 JP-5 Kerosene Fractions b) IRFNA Inhibited Red Fuming Nitric Acid c) UDMH Unsym Dimethyl Hydrazine 85-100 General purpose attitude control... 

IRFNA (inhibited red fuming nitric acid) 84.4% HNOa-14% N204— 1% H2O-0.6% HF... 

Nitric acid has been used in various forms as the oxidizer in liquid-fueled rockets. These forms include red fuming nitric acid, white fuming nitric acid, mixtures with sulfuric acid, and these forms with HF inhibitor. IRFNA (inhibited red fuming nitric acid) was one of 3 liquid fuel components for the BOMARC missile. 

The extensive application of N204 in pure form to rocketry is a fairly recent development however, its use as a stabilizer and freezing point depressant for HN03 dates back more than 15 years. Mixtures of HN03, N204, and small amounts of water and HF are referred to as inhibited red fuming nitric acid (IRFNA) or without the HF (a corrosion inhibitor) as merely red fuming nitric acid (RFNA). 

All oxidizers being evaluated for use in rocket engines are carefully examined to determine their compatibility with the materials with which they will be in contact. In some cases elaborate steps are necessary to develop passivation techniques that permit extended storage of these oxidizers. One of the classical cases in recent years was the development of inhibited red fuming nitric acid (IRFNA) for use in aluminum tanks. 

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