Description
Processes include acid pickling and acid bright dip (phosphoric, hydrochloric, hydrofluoric, chromic, nitric, and sulfuric acids), alkaline immersion (NaOH, KOH, borax, tetrasodium pyrophosphate), and salt baths (NaOH). Nitrogen oxide gases are released from the mixture of nitric and sulfuric acids commonly used in acid bright dips. Pickling of silver with sodium cyanide generates a cyanide mist. Triethanolamine and cobalt are additives sometime used in alkaline dips of aluminum to modify the etch rate. [Burgess, p. 49-57] See the agent "Strong inorganic acid mists."