This site uses cookies. By using this site, you agree to the use of cookies. For more information, please see the Privacy page Privacy.

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

Boehringer Ingelheim Pharma GmbH & Co. KG

CitriSurf®2310, Gel

Stainless steel surfaces derust & passivate with gel: CitriSurf®2310 is a high quality blend of chemicals formulated for cleaning, rust removal and passivation of stainless steel products. It is provided in a high viscosity form for easy application on weld joints, vertical surfaces, and other large items or areas that cannot be conveniently dipped in a bath. CitriSurf®2310 is specifically designed to provide low cost and efficient removal of all rust and free iron from the surface of stainless steel and other metals, providing the highest chrome oxide levels possible.

Physical Properties
Specific Gravity 1.1
Viscosity thixotrop
From High Viscosity Liquid*
Chemical Composition Citric acid, water, inert and proprietary ingredients
Operating Temperature Room temp or higher (max. 75 °C)
Flash Point None
Water solubility 99%
Normal working concentration Use as received
pH at working concentration ~2.0
Packaging 5 liter or 20 liter plastic containers
* A liquid version of this product is available as CitriSurf®77plus

Application Procedure

  1. To assure best results, the parts to be treated should be thoroughly cleaned to remove dirt, oils, and grease with an appropriate cleaning solution prior to treatment with CitriSurf®2310, although it is a very good cleaner by itself if used properly. If thorough cleaning is not possible during use in the field, wipe the surface free of dirt and oils prior to application.
  2. All equipment, mixers, applicators or pumps should be clean and dry prior to use. Only containers constructed of polypropylene, polyethylene, or other acid resistant plastic or stainless steel should be used to hold or store this product.
  3. CitriSurf®2310 is intended for use without dilution, but if it is advantageous or necessary to slow down the reaction rate or lower the viscosity, it may be diluted with water at a maximum 1 to 1 ratio by volume. For more aggressive cleaning, use longer times, higher temperatures, and/or higher concentrations. Time, temperature and concentration of the product should be tested prior to use in production. Please contact the manufacturer for assistance if necessary to determine the best formula and conditions for your product. Each application is different!
  4. Prior to use, mix thoroughly by shaking or stirring. CitriSurf®2310 should be applied liberally to the surface to be treated with a sprayer, brush or roller. Coverage is approximately 250 square feet per gallon. Wait approximately 10 to 30 minutes, depending on the application, and then rinse the product from the surface completely. Repeat process if needed to obtain desired results. Difficult rust or corrosion must be tested to determine the exact best conditions for removal. If heavy rust needs to be removed, Scotch BriteTM or other non iron containing abrasive may be helpful.
  5. Note: CitriSurf®2310 must remain moist during the treatment period. When using CitriSurf®2310 in direct sunlight or other hot environments, it may be necessary to periodically sprinkle the surface lightly with water to keep the CitriSurf® from drying.
  6. Rinse thoroughly with clean water and dry completely in air immediately or proceed with post-treatment to obtain the desired results. Drying can be accelerated by use of a hot air oven or other drying medium such as an air blower (hair dryer) to attain a clean, dry surface prior to post treatment or packaging.
  7. We recommend a professional pressure device to apply the gel evenly


The cleaning components of CitriSurf®2310 thoroughly remove all traces of oil and grease from the surface. The special citric acid then removes the free iron ions from the top molecular layers. This creates a positive change in the chrome-iron ratio which leads to a better rust resistance or passivation of the surface. There is no negative impact on the function of the passivated part. Welded seams and soldered joints are also not affected; they are only rid of impurities containing free iron. Even other materials such as aluminium can be treated with CitriSurf® in order to remove iron components and ferrous impurities which have been brought to the surface by mechanical processing. The specified concentrations and times refer to the use on stainless steel. For other materials, specific parameters must be developed by means of trials and/or consultation with the developer or manufacturer of CitriSurf®.

Notes on Use

Although very safe in normal use, CitriSurf®2310 is a Citric Acid based material, and as such it may cause irritation to exposed surfaces of the body. See Material Safety Data Sheet before using this material. Rubber or plastic gloves should be worn to apply the product to the surface or to wipe it dry. Do not apply CitriSurf®2310 to electrical wiring or other conductive material that is connected to electrical current without first turning off all electricity! CitriSurf® is a water based conductive material. Serious injury or death con occur from electrical shock. Do not leave concrete or carbon steel exposed to CitriSurf® for any period of time. Damage to these materials will occur with prolonged exposure.


Dispose of according to all federal, state and local regulations.


CitriSurf®2250 should be stored at temperatures between 10 °C and 40 °C in 316 stainless steel or approved plastic containers (polyethylene or polypropylene). (If accidentally frozen, thawing will return product to normal.)

Technical Services

For technical assistance, please contact MKK GmbH.


CitriSurf®2310 meets all of the requirements of ASTM A-967 and AMS 2700 specifications.

Testing of your products with CitriSurf® before using in production is recommended. Every product and facility is different, and requires testing to ensure that CitriSurf® is compatible with the particular situation. No warranty is implied, or may be given in writing or verbally without the written permission of Stellar Solutions, Inc.