Lecture 9 Flashcards
What is a protective coating?
A layer of material applied to a a surface of another material with the intent of inhibiting or preventing corrosion.
What is a barrier coating?
moisture barrier
Have a quick drying time and provide an outstanding resistance to corrosive chemicals, heat and UV. Example: coal tar epoxy coatings.
What are the two types of barrier coating?
Water based coating: cured at ambient temp. Non hazardous with low-flammability
Powder based coating: cured under controlled high temps. Used to produce the surface of many white appliances, such as washers, dryers and fridges.
What is an inhibitor coating?
It is a protective barrier .
passivation layer which prevents contact with water, chemicals and other corrosion..
What is a sacrificial coating?
thin metal layers that have lower electrode potential values . It builds a clear barrier.
What is an example of sacrificial coating?
Zinc-coated steel or galvanised steel
What are the benefits of sacrificial coating?
Mostly water based
Fast and easy to apply
Breathable
Invisible
In anodic coatings, why the coating metals possess lower reduction potential than base metal?
Because the process of anodizing involves the formation of an oxide layer on the surface of the base metal. This oxide layer is formed by the electrochemical oxidation of the base metal in an electrolytic solution.
Is protective coating cost effective?
In many cases, protective coatings can be cost-effective because they can significantly extend the lifespan of the protected surface and reduce the need for frequent maintenance or replacement.
