CitriSurf®
CitriSurf® supports the cleaning and passivation of stainless-steel surfaces for applications with high requirements for surface cleanliness, rinsing quality and documentable process reliability.
Cleanroom and Ultra-Pure Water Technology
CitriSurf® offers citrate-/citric-acid-based cleaning and passivation for stainless-steel components in demanding process environments. For cleanroom and ultrapure-water applications, it is not only the chemical treatment that matters, but the entire sequence of pre-cleaning, passivation, thorough rinsing, drying and documentable release. ASTM A967/A967M explicitly lists citric acid as an approved passivation route for stainless-steel parts and requires thorough rinsing after treatment.
Cleanroom and Ultra-Pure Water Technology
In cleanroom and ultrapure-water applications, free iron, processing residues and iron-containing foreign matter can impair the surface quality of stainless steel. The decisive factor is therefore a process that leaves the surface chemically clean and integrates safely into the subsequent process. ASTM A967/A967M describes chemical passivation treatments for stainless-steel parts, provides recommendations for cleaning and passivation, and contains alternative test methods for confirming effectiveness.
Citrate-/citric-acid-based passivation is an established alternative to nitric-acid-based processes. CitriSurf also explicitly positions its products in the context of ASTM A967 and AMS 2700.
Cleanroom and Ultra-Pure Water Technology
So that you do not have to search through several product pages first, the typical assignment is shown here directly in overview form.
CitriSurf 3050 is designed for applications with very low foam formation, especially systems with air agitation and CIP systems. This variant is therefore the obvious choice when the process should not only passivate, but also run with low foaming.
CitriSurf 2310 is the gel variant for applications where rust also has to be removed in addition to passivation. It is suitable for local areas, vertical surfaces and larger parts that cannot conveniently be immersed.
When components cannot reasonably be treated in an immersion bath, CitriSurf 2210 is the suitable gel variant. It is designed for weld seams, vertical surfaces and larger areas.
If components are heavily contaminated with oil, grease or production residues, highly alkaline pre-cleaning before passivation is useful. KleerKleen 4002 is designed precisely for this pretreatment before passivation with CitriSurf.
Cleanroom and Ultra-Pure Water Technology
Before passivation, oils, greases, particles and production residues are removed. For more heavily contaminated parts, this may be done with separate pre-cleaning, for example with KleerKleen 4002.
The suitable product is then used depending on component, geometry and process form: in an immersion bath, in a low-foam system, as a gel on surfaces or locally by spray. ASTM A967/A967M explicitly lists immersion treatment with citric acid solution as an approved route.
After treatment, the parts are rinsed thoroughly. ASTM A967/A967M requires thorough rinsing immediately after removal from the passivation solution in order to stop the chemical reaction on the stainless-steel surface. Depending on requirements, DI water, demineralized water or ultrapure water can be used.
After rinsing, the parts are air-dried and should be left to rest for one hour. During this time, the formation of the optimal passive layer is completed. Do not use a vacuum oven.
Finally, the treated parts can be visually inspected, documented and released according to customer-specific criteria.
Cleanroom and Ultra-Pure Water Technology
CitriSurf is suitable for stainless-steel components in demanding process environments, for example for:
· components in cleanroom systems
· parts in ultrapure-water systems
· fittings and pipeline components
· tanks and vessels · brackets and assembly-critical components · tools and stainless-steel parts for pharmaceuticals, laboratories, semiconductors and medical technology
Cleanroom and Ultra-Pure Water Technology
Passivation of stainless steel should not only be chemically effective, but also process-reliable and traceable. In many applications, the focus is therefore not only on the product, but also on cleaning, rinsing quality, drying and documentation.
Depending on the application, visual inspection, water-break testing, residual contamination testing or customer-specific release criteria may be part of the process.
FAQ
Yes. ASTM A967/A967M explicitly lists immersion treatment with citric acid solution as an approved passivation route for stainless-steel parts.
ASTM A967/A967M lists both nitric-acid and citric-acid treatments as approved chemical passivation routes. CitriSurf ® positions its products as citrate-based alternatives within this standards logic.
For conventional immersion-bath applications, CitriSurf ® 3050 is often the suitable starting point, including for very low-foaming systems.
For large parts, surfaces and weld seams, CitriSurf ® 2210 is the suitable gel variant. If rust also has to be removed, CitriSurf ® 2310 is useful.
CitriSurf ® 77plus is intended for smaller areas and spot applications.
Whenever oil, grease or heavier production residues are present on the surface. In such cases, alkaline pre-cleaning can be performed upstream. KleerKleen 4002 is designed precisely for this pretreatment.
Rouging occurs due to high temperatures in pure- and ultrapure-water systems. Rouging is successfully removed with the derouging agent CitriSurf ® 8050.
Are you looking to clean and passivate stainless steel components for cleanroom or ultrapure water applications while selecting the right product for your process? If so, we’ll tailor the cleaning, passivation, rinse quality, and release criteria to your specific application.
Exclusively from MKK GmbH, Oldenburg
Order by email: order@citrisurf.de
Please note:
- Provide your VAT ID
- Billing address and delivery address required
- Orders before 12:00 noon: usually shipped on the next working day
- Delivery date = shipping date (transit times depend on the logistics provider)
