Nitric Acid Process
Passivation is an effective metal finishing process that prevents corrosion by removing free iron from a surface. Although citric acid has become increasingly popular for passivation, the treatment traditionally uses nitric acid as the preferred oxidant. The process works by using nitric acid to create a protective oxide layer on the metal’s surface so that it’s less likely to react to the air and corrode.
At Advanced Deburring & Finishing, we have nitric acid passivation equipment to protect your stainless steel parts from rust and corrosion.
What Is the Nitric Acid Process?
Nitric acid is a highly corrosive inorganic acid and oxidizing agent. In addition to being an effective oxidant, nitric acid is an essential ingredient for manufacturing fertilizers, rocket propellants and certain explosives. The acid is strong and colorless, but it decomposes into a yellowish solution of water, nitrogen dioxide and oxygen.
Using nitric acid for the passivation of stainless steel is a proven process that dates back to the 1900s. Nitric acid is an inexpensive raw material and is effective on most stainless steel grades. You can also use numerous techniques to optimize the performance of nitric acid when working with a variety of steels.
A NITRIC ACID PASSIVATION SYSTEM CASE HISTORY
Nitric Acid Passivation Systems for precision aerospace components consist of five stages in MK Immersion Washers. The line runs from right to left. Ventilation ductwork is provided for all wet stages. Roller conveyor sections are on each platform and between stages as required to provide smooth lateral transfer of baskets from stage to stage.
Construction materials include 304 stainless steel, 316L stainless steel alloy 20Cb-3 heating elements and Nema 4 X control panels.
How Does the Nitric Acid Process Work?
Because nitric acid is a highly corrosive acid that emits hazardous fumes, using a ventilation system is essential when working with it. What’s more, you should also ensure that you’re able to properly dispose of the nitric acid after use.
This is the nitric acid process:
- Wash: During the nitric acid pretreatment, the parts are batch-loaded into 18″L x 18″W x 6″H stainless steel baskets and placed on the first transport elevator in Stage One. Using a high-alkaline detergent at 170 degrees F, the parts are washed using vertical agitation.
- Rinse: The basket is laterally transferred over special platform roller conveyor sections to Stage Two. Using hot water at 150 degrees F, the parts are rinsed using vertical agitation.
- Passivation Using Nitric Acid: The basket is laterally transferred over special platform roller conveyor sections to Stage Three. Using a 25% solution of nitric acid at 135 degrees F, the parts are passivated using vertical agitation.
- Rinse: The basket of parts is then laterally transferred over platform roller conveyors to Stage Four. Using DI water at 150 degrees F, the parts are rinsed using vertical agitation.
- Hot Air Blowoff Drying: The basket of parts is then laterally transferred over platform roller conveyors to Stage Five. Using hot air at 150 degrees F, the parts are dried. Ramco Hot Air Knife Blow-Off Dryers get maximum evaporation and provide rapid drying without excessive heat. This concludes the nitric acid process.
Our Nitric Acid Passivation Equipment
Our nitric acid passivation systems include multistage semi-automated MKT, MKD and MTT consoles from Ramco. The ideal model for your application will depend on:
- Batch load size and weight
- Cleanliness levels of the batch
- Required throughput per hour
- Grade of the steel parts
In addition to these systems, we also use Ramco Hot Air Knife Blow-Off Dryers to speed up the drying process without requiring excessive heat.
Enhance Your Nitric Acid Process With Advanced Deburring & Finishing
At Advanced Deburring & Finishing, we’ve provided customers worldwide
with innovative finishing and cleaning solutions since 1986. We’re committed to helping our clients achieve high-quality finishes while lowering their overall costs and increasing their return on investment. As part of our ongoing commitment to customer service, we’ll consult with you on process development to create safe, reliable equipment that streamlines your operations.
Our team of experts has the tools and industry knowledge to solve your finishing or cleaning issues. We can maximize your efficiency and improve your bottom line by connecting your company with the most advanced technologies and enhancing your equipment and operations.
When you choose to partner with Advanced Deburring & Finishing, one of our knowledgeable sales engineers will schedule a visit with you to examine your setup and determine the best solutions for your application. We’ve worked with clients in aerospace, transportation, automotive manufacturing, medical manufacturing and more to increase productivity, safety and profits.
Learn More About Our Nitric Acid Passivation Systems
Our nitric acid passivation systems can protect your stainless steel parts from corrosion. What’s more, we carry an extensive inventory of finishing and cleaning machines and components to match your project requirements. Contact us online today to learn more about our products, or call one of our representatives at 717-764-1056.