For several years, the passivation industry has followed the strict requirements of the Federal Standards in utilizing possibly dangerous nitric acid baths during stainless steel passivation. Even though there are industries who have effectively utilized citric acid, the majority of U.S. market, including Salt Lake City preferred to use nitric acid.
The Less Hazardous Alternative
Unbeknownst to many, citric acid is easy to use, safe and organic. If industries were able to formulate it correctly, the citric acid would provide them outstanding performance with substantial cost savings. The said acid is the similar acid you can find in oranges and other citrus fruits. Over 99 percent of citric acid sold is for the use of beverage and food products, as well as, disinfectants and cleaners.
Peak Finish shares that the notion of using citric acid for stainless steel passivation isn’t really a new concept. The Germans who worked in the beverage industry first developed this several years ago. They wanted to get rid of the iron on the surface containers that ruined the taste of their beverage. Suffice to say, the nitric acid passivation systems before couldn’t offer the extent of passivation needed.
Other industries just began utilizing citric acid for several reasons, such as the government standard QQP3C. The industry has abided by these standards that required them to utilize solely nitric acid or nitric acid combined with sodium dichromate.
The Government’s Move
The government provided very little motivation to avoid using nitric acid for it delivered the specifications needed by the product. However, recent events have changed the circumstances wherein the Defense Department voided QQP35C in place of the new ASTM Standard A967.
The regulators, including EPA, finally identified the safety benefits of citric acid formulations to the environment. They say that the citric acids aren’t only biodegradable, but rinsed waters can go down the drain as long as they meet local pH regulations. If the industry correctly formulates it, the citric acid can provide them exceptional results during the passivation of virtually any stainless steel product. They can also use it to brighten, passivate and clean other metals.
The industries who are already utilizing citric acids include aerospace, automotive, semiconductors, medical devices and fasteners. It won’t be long now before all the other industries follow the same route, especially with the new regulation in place.