Galvanic corrosion occurs when two different metals are touching each other in the presence of an electrolyte. As the process continues, one of the metals will deteriorate rapidly as electrons flow steadily to the other metal. Aluminum and its fasteners can corrode if exposed to salt water. Knowing the process and how to prevent it will help you make the right fastener choices. The wrong kind of screws used to fasten aluminum base metal can result in a chemical reaction that will quickly damage the aluminum. The right kind of fasteners will not have the same reaction.
Can I Use Zinc Plated Screws With Aluminum
Galvanized steel screws, on the other hand, are coated with a corrosion-resistant coating, mainly zinc, which is not nearly as strong as aluminum. The zinc plating prevents the underlying steel from coming into contact with the aluminum, and the likelihood of corrosion of the aluminum is minimized dramatically.
Is Zinc Plated Ok With Aluminum?
It is also important to note that aluminum cannot be treated in the same way as steel substrates. Aluminum can be zinc plated by a zincate process first followed by either cyanide or acid zinc plating solution. You are unable to plate directly on aluminum-based materials.
Is Yellow Zinc Compatible With Aluminum?
Both zinc and aluminum are extremely resistant to rust, so it will not be a problem for you.
What Screws Can I Use With Aluminium?
Many people are concerned that stainless steel fasteners will not work with aluminum due to the possibility of galvanic corrosion between the two two very different metals.
For fasteners and aluminum sheets, stainless steel is the preferred material.
Screws, bolts, nuts, seeds, or other products that can be used with aluminum products are among the best fasteners for aluminum materials.
Will Zinc Screws React With Aluminum?
Because of the small change in the potential between the two metals and the emergence of an insulating film on the aluminum’s surface, there is only a slim chance of retaliation.
In several instances, condensed water does not have enough conductance to begin the corrosion process.
If possible, the best alternative to this kind of corrosion is to create an insulation barrier between two dissimilar metals.
For more details on hot-dip galvanized steel in contact with dissimilar metal, see AGA’s Dissimilar Metals guide, which is published by AGC.
What Metals Should Not Be Used Together?
Can You Use Galvanised Screws On Aluminium?
Galvanized steel screws are coated with a corrosion-resistant coating, mainly zinc, which is not as effective as aluminum.
They’ll rust quickly, as well, so they’re not a good idea for fastening aluminum.
As with carbon steel screws, a plated stainless steel screw is less likely to corrode aluminum.
A high-quality coating is particularly resistant to rusting; zinc and aluminum flakes coated screws are more resistant than a plated screw.
The zinc plating prevents the underlying steel from coming into contact with the aluminum, and the risk of corrosion is reduced.
Can You Put Brass And Aluminum Together?
In the marine environment, aluminium and brass should never come into direct contact with one another.
On the galvanic scale, the two metals are just too different.
The further apart metals are on this scale, the more dissimilar they are.
One will be anodic and the other cathodian. In this case, the aluminum will become the anode, and as most boaters know, an odes dissolve in seawater. In your case, the fittings with the extra bushings shown are done correctly and as the ABYC would recommend in its specifications for this kind of assembly.