Astro Pak has over 60 years of experience perfecting our passivation chemistries and processes. We bring that expertise, along with our state-of-the-art equipment and highly trained personnel, on-site to your facility to perform pre-operational or maintenance cleaning and passivation on your systems and equipment.
For components, parts, and sub-systems that can be serviced out-of-place, Astro Pak’s nationwide shop facilities are well suited to affordably meet your cleaning requirements. We have state-of-the-art facilities that can accommodate parts of all sizes and volumes, including dip tanks up to 40ft and overhead bridge cranes with 7.5-ton lifting capacity for oversized parts. Additionally, we offer pick-up and delivery services as well as cGMP compliant documentation packages at the end of each job. Our highly skilled technicians and controlled environments ensure consistent quality and compliance to industry and customer-specific standards.
During an audit tour from a regulatory agency, the lead Astro Pak technician had answers for things that I did not even know that I had to worry about.
-Senior Utilities Engineer,
Our Passivation Standards
Astro Pak prides itself on a long legacy of meeting and exceeding the standards set forth by a variety of organizations in numerous industries, including ASTM, ASME, SAE, SEMI and FDA, to name a few.
Trust the Experts in Passivation
Our proprietary Ultra Pass® passivation process is renowned for its environmentally friendly blend of high-purity ingredients, including chelants that bind with metal ions rendering them incapable of redepositing on surfaces. As a result, the material handling requirements and other impacts on-site are greatly reduced.
Beyond that, the Ultra Pass® passivation process provides superior results, capable of producing an optimized passive layer on the surface of stainless steels, yielding unmatched corrosion resistance. Our studies have shown that the chrome to iron ratios achieved by Ultra Pass® passivation far exceeds ASME BPE recommended minimums and meets or exceeds the requirements of many industries including semiconductor, aerospace, pharmaceutical, and biotechnology.
Frequently Asked Questions
Most stainless steels (especially austenitic types) can be passivated, but levels of improvement vary between alloy type and quality of surface chemistry present.
Passivation removes iron and small amounts of very light rouge from the surface thus enhancing corrosion resistance. Heavier amounts of rouge must be derouged to prepare for the passivation treatment.
That depends upon the quality level desired and the sensitivity of the product process to low levels of iron or iron oxides. It also depends upon the methods used to refine the final product, including filtration, evaporation/drying, or iron’s effect on the biotech process. Generally, lightly discolored wipes or faintly visible rouge is acceptable, distinctly colored wipes or significant surface discoloration is unacceptable. Use of filtration testing to measure the amount and size of particles in the process fluids can be used as a guide to evaluate the effect of rouge coming off the surface.
By taking samples before and after the passivation treatment and testing them for chromium to iron ratio, one can quantify the quality of the passive film. The semi-conductor and pharmaceutical industry have set stringent measurable standards for systems or levels of purity.
We conduct iron readings of the solution circulating the system. At the beginning of the passivation process, iron concentration levels start out high and gradually taper off and plateau when all the iron is removed. Additionally, we know that 2% citric will hold in solution 1% iron (1 % iron is equal to 10,000ppm). We typically see iron concentration levels in the 1 to 50 ppm levels in our passivation. Our proprietary blend uses substantially higher percentages of citric to ensure that all iron is captured before the acid is exhausted
No, only on a molecular level. Passivation enhances the chemistry of the passive layer by increasing the ratio of very stable chromium atoms to the more reactive iron atoms in the upper three to five atomic layers of the metal’s surface.
Passivation does not remove material. Passivation enhances the ability of the treated surfaces to resist corrosion.
As the pit develops, it starts out shallow and deepens but the debris inside the pit cannot be removed. The pitting process will continue until it creates a hole in the pipe or surface.
Generally speaking – No. However, one can consider that corrosion undoes passivation by attacking the passive film. Reducing environments will undo passivation and render the surface active or corroded. The passive layer is very thin (2 to 5 molecular layers) and can be eliminated by welding or polishing, by reducing environments and corrosion.
Derouging is the removal of visible iron oxides and other metal oxides from the surface. Passivation is the removal of iron or iron oxide from the surface in the passive film or top 3 to 4 molecular layer. Derouging uses stronger acids to remove large visible accumulations of iron oxides to a visually clean condition. Passivation is designed to remove the small amount of free iron from the visually clean surface.
The passive layer is very thin (2 to 5 molecular layers) and can be removed by welding, polishing, by reducing environments and corrosion.
Typical passivation process takes 8 to 10 hours in small systems and generally 12 hours for larger systems. Derouging alone can take 4 to 24 hours depending upon the condition of the surface.
Passivation enhances the chemistry of the passive layer by increasing the ratio of very stable chromium atoms to the more reactive iron atoms in the upper three to five atomic layers of the metal’s surface.
Yes. Visually the surface looks like it has spots (white, black or brown) hazing or roughness. The pits need to be sanded/polished out and electropolished. If the pits are very deep, then the surface will need to be ground, welded and then polished and electropolished.
Regular scheduled preventive maintenance and reduction of corrosive conditions – i.e reduce the use and concentration of chloride containing solutions or choose more resistant alloys where chlorides and heat are present.