Corrosion impacts all aspects of industry; automotive, construction, transportation, production, maritime, and manufacturing to name a few. Not only can it be an eyesore, but it can be costly too. In fact, it’s estimated to cost the US economy $276 billion alone, contributing 3.1% to the countries total GDP.
So, how can corrosion impact adhesives and what can be done to prevent costly decay?
Within this blog, I’m going to briefly outline the types of corrosion, the impact it has on adhesives and a few tips on prevention. However, if you’re left unsatisfied, or want some more information, feel free to contact one of our experts on the number above.
Corrosion: Degradation or destruction of a material and it’s critical properties due to chemical, electrochemical, and other reactions.
The four main types of corrosion:
- Uniform corrosion:
This is where the surface layer of metal/alloy rusts due to environmental factors. Uniform corrosion is mostly common amongst ferrous metals and alloys that are uncoated.
- Galvanic corrosion:
Galvanic corrosion is driven by corrosion potentials of dissimilar metals when in an electrolytic solution (water). The lowest corrosion potential metal becomes the anode, and the highest the cathode.
- Electrolytic corrosion:
Similar to galvanic corrosion, with the difference being that it does not require an electrolytic solution. There must be an external source of electromotive (EMF), such batteries, electric generators etc.
- Filiform corrosion and Crevice corrosion:
Formed through ion gradients, which generate anodic and cathodic areas on the metal, this is the most common type of corrosion.
How are adhesives affected?
Oxides associated with a corrosion reaction can break down the boundary layer at the adhesive-adherend interface. In turn, this will begin to deteriorate the forces within the adhesive itself. It’ll begin to soften, de-laminate and lose its strength properties.
How can corrosion by prevented?
- The use of metals:
Choose a metal that is more resistant to metals (aluminium, stainless steel, chrome etc).
- Protective coatings:
Use paints and/or powder coatings – this reduces the oxidation on the metal surface.
- Design modification:
Avoid crevices that can attract dust. This can attract water, which may ultimately lead to corrosion.
- Anodic and cathodic protection:
Use less/more reactive coatings which can inhibit oxidisation on the bulk metal material.
Did you know…
Some metals oxidise to form protective outer coatings which can prevent further corrosion?
In 1886 the statue of liberty was brown in colour, but after 30 years fully oxidised into the green shade we see today!
