Citric passivation is a fast, cost-effective and environmentally friendly method of increasing corrosion resistance for stainless steel parts that is increasingly in demand in aerospace and manufacturers.
Stainless steel is naturally resistant to corrosion but machining introduces free iron that can create initiation sites for corrosion that will continue to spread unless it is removed. Citric passivation removes free iron contamination.
Stainless steel parts are immersed into an oxidizing bath consisting of naturally occurring acids found in oranges and other citrus fruits, which is biodegradable and more environmentally friendly than nitric passivation. The citric acid bath creates a thin yet dense, protective oxide layer that makes stainless steel parts corrosion-resistant and clean once again.
Our citric passivation services conform to ASTM A967, ASTM A380, AMS 2700, and QQ-P-35C.
As explained in Euro Inox’s publication Pickling and Passivationg Stainless Steel, “Steel delivered from manufacturing mills and reputable stockholders will be fully passive. The treatment may be needed however on intricately shaped machine parts. In these special cases, the supply of oxygen to all the newly formed surfaces may be restricted, resulting in the natural passivation process taking longer to complete, than on the open, exposed surfaces. There is a danger that if parts like these are put straight into service in an environment normally considered suitable for the particular steel grade used, they might not be fully passive and suffer unpredictable corrosion. Passivation treatments done under these circumstances eliminate these unnecessary corrosion risks.”
Only electropolishing removes burrs, micro cracks and other contaminants by dissolving 0.0005″ to .001” of the “skin” within a tolerance of +/- 0.0002” for stainless steel as well as titanium, Nitinol and a wide variety of alloys. Electropolishing eliminates the need for additional metal finishing processes like hand deburring, tumbling, cleaning, and even passivation.
If your spec calls for passivation but you’d like to learn more about the superior results electropolishing provides, we can electropolish a sample of your parts for no charge and facilitate updates to your engineering change order (ECO) process.
Whether electropolishing or passivation is the right process for you, we offer the highest-quality finishing services. Our state-of-the-art 45,000 SQFT facility operates 3 shifts, 5 days a week. We offer expedited service, can handle parts of any size, and provide customized processing for every part, including custom racking. Start with a sample finish of your part for free.
Our tightly controlled quality process and ISO 9001 and ISO 13485 certifications make us the preferred partner for many medical device manufacturers across the globe. From implantable devices to surgical instruments, electropolishing is a single-process treatment that results in biocompatible, safe and ultra clean parts.Learn More
We offer aerospace vendors and original equipment manufacturers our signature metal finishing services to increase fatigue-resistance for their metal parts, rendering them capable of withstanding the stress and corrosion that comes with long-term use. Surface abnormalities lead to part failure, but with electropolishing, parts become more reliable and long lasting.Learn More
Our strict adherence to industry standards ensures that pharmaceutical components are electropolished in accordance with ASTM B912 and ASME BPE specifications. These products are clean and smooth, corrosion resistant and contaminant free.Learn More
Corrosion resistance and microfinish improvement are essential for critical automotive parts, making electropolishing an increasingly beneficial option for automakers. Electropolishing both interior and exterior auto parts ensures they will resist premature failure and function at an optimal level.Learn More
Notable examples of appliance parts we electropolish are 400-series stainless steel alloys used in many consumer appliances. Our metal finishing services help increase corrosion resistance for these parts, and by removing the outermost layer of metal withelectropolishing the durability and longevityof these appliance components is increased.Learn More
We have a long history of working with the food and beverage industry. Electropolishing materials for this industry eliminates the buildup of bacterial biofilms, as well as keeping the equipment free of contaminants like Salmonella. When it comes to food and beverage processing equipment, safety and cleanliness are of the upmost importance and electropolishing delivers the level of sanitation required by a number of regulatory agencies.Learn More
From robotics to heavy mobile equipment, the uses of electropolishing in the hydraulics and pneumatics industry are many. By helping prevent premature part failure, electropolishing reduces the amount of downtime and increases the life cycle of these components. Proper surface finish and cleanliness is key in this industry, and electropolishing attains the finishour customers require.Learn More
Improving conductivity and performance is just one benefit electropolishing offers for electronics parts. The surface finish is improved by as much as 50 percent, removing imperfections from the material without removing a lot of material removal from the component.Learn More
Even in a year of unprecedented manufacturing obstacles and supply chain bottlenecks, medical manufacturers have bigger challenges.
Electropolishing removes the recast layer created during electrical discharge machining (EDM), improving the fit, function, and finish of metal parts.
Among the most demanding surface finish requirements of any industry, the specifications, standards and quality assurance processes that cover components used by the semiconductor industry impose metal finishing criteria that leave nothing to chance.
Read our e-guide to learn more about electropolishing’s track record of high-quality results in tackling some of the most common metal surface problems manufacturers face.