Working with aluminum and brass together should always come with a bit of caution.
When they are both used in an application that involves direct contact between them, they will corrode. And if there is water present, the corrosion – and potential fusion – happens at a much faster rate.
This reaction between aluminum and brass is known as Galvanic Corrosion.
What is Galvanic Corrosion?
Both metals, aluminum and brass, work beautifully on their own. Even when in contact with water, they still do well and will not corrode. But when they come together, their story takes a different turn.
Galvanic corrosion is a reaction that occurs when an anode and a cathode come in contact with an electrolyte. This electrochemical process occurs when two dissimilar metals are used in an application — in direct contact with one another.
Let’s take a closer look at what this means.
When linked together, the anode (in this case, the aluminum) will begin to corrode over time. The cathode (the brass), will not. When the metal comes in contact with an electrolyte, such as water or condensation, the rate of the aluminum’s corrosion increases significantly — wasting the metal away.
How to Safely Use Aluminum and Brass Fittings Together
While stainless steel, titanium, and nickel all work well with aluminum and avoid galvanic corrosion, they are not always the ideal choice for a project or application. Sometimes brass is just a better fit.
Believe it or not, by taking a few extra steps, you can successfully use aluminum and brass fittings together — and reduce the chance of any unwanted interaction between them. Here are a couple of ideas.
Isolate Each Metal
If you separate the aluminum from the brass, you avoid contact between them. The result? They do not touch and extinguish the corrosion and fusion that would otherwise take place between them.
Isolating the metals can be done in different ways. Two popular methods would be using non-conductive materials, such as gaskets or certain coatings. However, depending on the application, this may not always be a feasible solution since leaks and open crevices may occur.
Add A Third Metal
If aluminum and brass have a negative relationship, why not place another one between them?
Choosing a metal, such as zinc, and placing it between the others will result in the new metal succumbing to corrosion. The zinc will become the anode, saving the other two.
Reduce Electrolyte Exposure
While it may sound like a simple option, reducing exposure to electrolytes isn’t always possible in every application. It is still something that could be considered, especially with the help of varnish.
Ensuring that your metals are covered in a protective varnish can reduce their interaction with one another when electrolytes are present. If you can only add the varnish to one, add it to the cathode, the brass.
Aluminum and Brass — And Unlikely Pair
Aluminum and brass are two incredible metals with highly sought-after properties. Both aluminum and brass have unique properties that make them ideal for various applications. Aluminum is lightweight, durable, and has excellent thermal conductivity, which makes it perfect for use in industries such as aerospace, automotive, and construction. Brass, on the other hand, is known for its high resistance to corrosion and excellent electrical conductivity, making it perfect for electrical applications, plumbing, and decorative purposes. If you choose to use them in your next project, be sure to take precautions against galvanic corrosion. Or, perhaps you want to take the time to uncover a better metal combination.
Atlas Bronze provides solutions to all your metal needs and has established itself as a leading distributor of bronze, copper, brass, iron, sintered products, self-lubricated bushings, and wear plates in the United States.