We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Materials

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is Dezincification?

By Jennifer Voight
Updated: May 17, 2024
Views: 37,009
Share

Dezincification of brass is a form of selective corrosion that happens when zinc is leached out of the alloy leaving a weakened porous copper fitting. This commonly happens in chlorinated water or in water that has high levels of oxygen and carbon dioxide. Signs of dezincification are white powdery zinc oxide coating the surface of the fitting, or yellow brass that turns red. Selective corrosion can be a problem when it weakens a fitting, leaving it vulnerable to failure and eventual leaks.

Brass is an alloy, or mixture, of copper and zinc. Since brass is a malleable metal that is easy to cast and has many desirable properties, it is often used in plumbing. When a brass alloy is made up of more than 15 percent zinc, there is an increased risk of selective corrosion because zinc is a highly reactive metal with a weak atomic bond. As the percentage of copper in the alloy increases, the risk for dezincification decreases.

There are two types of dezincification that can occur that are often more common in different parts of the world, depending on local conditions. The plug type is localized and deep. Neutral or alkaline water that is high in salt and warmer than room temperature may cause zinc to leach. Over time, penetration can cause holes and leaks or failures in threaded parts.

Uniform dezincification happens over a broader area than the plug type, thinning the wall uniformly. Slow water flow or stagnant water, especially when the water is high in oxygen and carbon dioxide, may make a fitting more susceptible to uniform corrosion. Slightly acid water that is low in salt and about room temperature may also facilitate leaching of zinc.

There are several methods to increase resistance to corrosion and zinc leaching. Fittings with less than 15 percent zinc are less susceptible to leaching and corrosion, provided there aren’t elements known to react with copper present in the water and aeration is minimal. Manufacturers may also add trace amounts of other elements to the alloy to ward off corrosion. Arsenic, antimony, phosphorus, and tin may be added to the alloy, with the addition of antimony being the most effective.

The use of dezincification resistant brass is becoming more common. Resistant brass is marked CR (corrosion resistant) in the United States. In the United Kingdom, it is marked DZR (dezincification resistant), and in Australia it is marked DR (dezincification resistant).

Share
About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By laurenb — On Jun 19, 2011

@Fasol - it doesn't leave, it just gets transformed. It reacts with the other metal to form a different product. For example, zinc can react with excess oxygen to form zinc oxide.

By Fasol — On Jun 17, 2011

If selective leaching means that the zinc is "leached" out, where does it go?

Share
https://www.aboutmechanics.com/what-is-dezincification.htm
Copy this link
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.