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"CitriSurf® is a perfect and environmentally friendly alternative to passivating with nitric acid!"

Boehringer Ingelheim Pharma GmbH & Co. KG


By means of the CitriSurf® passivation method, any impurities are dissolved from the surface, and the formation of a passive layer is accelerated. This improved passive layer is more durable compared to the natural passive layer or the passive layer obtained by the use of nitric acid.

  • Soaking-bath passivation 
    For large quantities of small components, the use of CitriSurf® 2250 is recommended. The concentrate is normally used at a dilution of 1:2–1:5.
  • Tank and pipeline passivation
    Here the solutions CitriSurf® 3050 or 3250 are used depending on the steel type. The special property of these concentrates is foam inhibition, allowing pump system and spray ball application.
  • Highly alkaline pre-cleaning
    For steel types with a higher sulphur content or carbon content, pre-cleaning with a cleaner with a pH value of >11 has turned out to be highly effective. KleerKleen™4002 is aligned with the CitriSurf® method.
  • Surface passivation
    For the passivation of surfaces of large machine parts, CitriSurf® 2210 is used. This gel-type product can be sprayed or painted on.
  • Rust removal and passivation
    If rust has already formed on the surface, it can be dissolved by use of the products CitriSurf®2310 and 77plus. The gel-type CitriSurf®2310 is sprayed or brushed onto rusty spots. 77plus uses a small spray bottle containing 500 ml which is used for smaller reworking. A double application not only removes the rust but also achieves passivation.