Definition - What does Protective Barrier mean?
A protective barrier is a physical layer on top of a corrosion-prone metal surface, and is intended to prevent corrosion. Protective barriers are added to metal surfaces by painting the surface with a non-metallic coat or plating with a metal.
Non-metallic coatings such as paints and corrosion resistant metal coatings are inert and simply create a barrier on top of the metal surface.
Reactive metallic barriers, on the other hand, form a protective barrier after being corroded. These types of barriers are called sacrificial because the integrity of the coating is compromised to create the protective layer.
Applying protective barriers to metal surfaces not only provides resistance to corrosion, but also can help prevent physical damage, add heat resistance and improve aesthetics.
Corrosionpedia explains Protective Barrier
There are many types of protective barriers that can be applied for corrosion protection. Each type of barrier provides advantages and disadvantages.
Choosing an appropriate protective barrier for an installation depends on what special qualities or properties are needed. Pipes transporting water in cold conditions, for example, could benefit from a coating that both prevents breakdown of the pipe as well as provides insulation. Other considerations include the cost, ease of application or removal, and durability. Although adding coatings cost money, they may save money over time by preventing the premature replacement of expensive parts.
Some materials, such as aluminum, create their own protective barriers by creating a thin film of oxidized material on the surface when exposed to air.
Cracks or scratches on a barrier can create weak points where corrosion can occur.
Protective barriers are prone to wear, which can remove the protective qualities of the barrier over time. Using specialized equipment such as tribometers, engineers can study how easily protective barriers can break down.