Our friends at ICCONS have helped to explain how to ensure that your choice of fasteners is compatible and prevent corrosion on your projects.
Galvanic corrosion, otherwise known as bimetallic corrosion, occurs when two metals of different nobilities (stability of metal) are in contact with the presence of an electrolyte like water.
The rate of corrosion will depend on the following main factors:
- The difference in the nobility of the metals
- The conductivity of the electrolyte (humidity, rainwater or seawater)
- Ratio of the less noble (anodic) to more noble (cathodic) metal
Galvani corrosion is typically seen in the less noble anodic material and the more noble cathodic material is not as heavily affected. As a basic rule of thumb, corrosion can be prevented by keeping metals of contact with water, or by using metals with the same nobility.
The chart below outlines the different types of metal and their nobility:
The more common considerations in choosing fasteners will include*:
Galvanised Steel VS Aluminium
Contact between a galvanized surface and aluminium is unlikely to cause substantial incremental corrosion
Galvanised Steel VS Stainless Steel Contact between a galvanized surface and a stainless steel surface is unlikely to cause substantial corrosion
Aluminium VS Stainless Steel Stainless steel is reactive with aluminium, and when a stainless steel screw is in contact with an aluminium base metal, the aluminium is likely to corrode.
Zinc Plated Vs Stainless Steel Stainless steel and the zinc in galvanized steel are very dissimilar and will react to each other.
Zinc Plated Vs Galvanised Steel There is no fear of galvanic corrosion when galvanized steel is in contact with other zinc coatings
Zinc Plated Vs Aluminium There is only a slight chance of a reaction because of the relatively small change in potential between the two metals
To find the right fastener for your project, view our range of products.
*A durability engineer should be consulted if galvanic corrosion is a concern for your project
To find the right fastener for your project, view our range of products.