Advantages of CitriSurf

There are alternatives to nitric acid passivation of stainless steel. There is data available showing that citric acid passivation is equal to or superior to nitric acid passivation.

Citric acid has been used very successfully for years in many industries. There is test data using salt spray, copper sulfate, palladium chloride, boiling water and high humidity on many grades of stainless.

Some of the advances that have been made in the last few years are:

  • Elimination of rust and corrosion problems on 410 ss that has been a problem for many years with nitric acid passivation (surgical industry).
  • Chrome oxide : Iron Oxide ratios on the surface of 316 stainless steel that are higher than ever obtained with nitric acid (semiconductor industry). Ratios as high as 12.7 to 1 have been obtained!!!
  • Complete elimination of passivation problems on orthodontic devices made of 316 stainless steel brazed with gold/palladium (orthodontics industry).
  • Cleaning and passivation of heat treated 455 stainless steel to pass water immersion tests and eliminate oxide coating to look like electropolished material (surgical industry).
  • Elimination of the need for Hydrochloric acid to remove heat treat oxides on 440C stainless steel (controls industry).
  • Improved corrosion resistance compared to nitric acid on 302 and 316 stainless steel. Elimination of rejects that were plaguing the customer (spring industry).

In all cases, it is being done successfully while saving money and providing a safer atmosphere for employees and the environment.

Environmental Information


The CitriSurf line of products has specifically been formulated to eliminate the safety and environmental problems of nitric acid and other mineral acids used in the cleaning and passivation of stainless steel. When used as directed, CitriSurf products yield excellent results without producing hazardous waste or NOx pollution in the air.

Waste water:

CitriSurf products are a high quality blend of chemicals formulated for the cleaning and passivation of stainless steel products normally without producing hazardous rinse solutions which require waste treatment prior to drain. Because the EM>CitriSurf products do not strip the nickel or chromium from the surface, the rinse water can normally be put directly to drain as long as the pH falls within local guidelines (normally 5.0-9.0, but local areas vary!). CitriSurf products are excellent at selectively removing the iron and iron oxides from the surface, yielding rinse water that can easily be drained.

When the master bath requires replacement, which is seldom, the bath can be treated easily to remove all possible contaminants that may be in the bath, so that the requirements of local, state and Federal regulations are all met. Consult our technical experts if you have any questions in this area.

Air cleanliness:

There are no NOx fumes emitted from the CitriSurf products. It is not necessary to scrub the air over the CitriSurf bath as required with nitric acid. When used as directed, the CitriSurf products do not produce fumes which are hazardous to individuals or to the environment as with nitric acid.