WILL POWDER COATING PREVENT GALVANIC CORROSION

WILL POWDER COATING PREVENT GALVANIC CORROSION

Galvanic Corrosion (also known as bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte.

Corrode simply means to eat away or be eaten away especially by chemical action as in the oxidation or rusting of a metal.

Powder Coating is a safe, dry finishing process that uses finely ground particles of pigment and resin to create a protective finish. Powder coat is low in toxicity and has low flammability.

Powder coating adds to the steel's durability, helping the frame to withstand damages better and last longer. Corrosion resistant. moisture and humidity can cause metal frames to rust. When applied to steel, powder coating provides a protective barrier that helps prevent corrosion.

Importance Of Powder Coating

Powder coating provides a hard finish that is tougher than conventional paint. Powder coating adds to the steel’s durability, helping the frame to withstand damages better and last longer. Because of its durability and resistance to abrasion and corrosion, powder coated steel require little to no maintenance. Moisture and humidity can cause metal frames to rust. When applied to steel, powder coating provides a protective barrier that helps prevent corrosion. Unlike other treatments that can easily crack, peel, chip, scratch and corrode, powder coated steel frames are more durable and can withstand the environment better. Because of this, colors stay brighter and vibrant longer than other methods. The powder coating process has little impact on the environment. It requires no harmful solvents and does not emit vapors or fumes like liquid paint does.

Powder coating is durable and could be used as a finish for a variety of surfaces, not just metal. The chemical bonds gives a superior coating that makes it suitable for both machinery and everyday items. It holds well to extreme weather and physical impact, meaning it’s resistant to scratches, abrasions, and chips.

Types Of Powder Coating

There are two types of powder coating

Thermoset

Thermoplastic

Thermoplastic Powder Coating finishes become liquid and very soft when heated. This eliminates chemical bonding. This process makes the powder coating both reversible and reusable.

Thermoplastic coatings tend to be thicker and hence more durable compared to thermoset coatings. For this reason, they can be used for a plethora of things from metal, auto parts, and even refrigerators. Thermoset Powder Coating is quite different in the fact that it forms chemical bonds once cured, making it impossible to recycle it. It is suitable for high heat areas because the bonds prevent it from melting away. This type is much cheaper compared to thermoplastic.

Different coatings also have varying lifespans. For instance, coatings that have fluoropolymers and urethanes can last longer. They are designed to withstand extreme conditions and are better suited for outdoor products. The longevity of the powder coating finishes will highly depend on several factors. These factors include the quality of preparation, type of powder coating used, and the environment in which the product is exposed. Powder coating finishes can last up to 20 years, but due to the consistent use, exposure to UV light, and outdoor environment may break it down faster.

Powder coating is well known for its adhesion and durability, and is commonly used for automotive parts, construction equipment, offshore platforms, and more.

However, the qualities that make powder coating such a great coating can become big challenges when you need to remove it.

The most common methods to remove powder coating are:

Chemical stripping

Burn-off in oven

Media blasting

Chemical stripping methods also known as caustic or solvents method works by causing the powder coating to dissolve, soften, and/or swell. At this point, the coating will fall off or have to be washed off. Chemical stripping can remove powder coating completely and evenly. Chemical stripping also has disadvantages. The toxic chemicals are dangerous to work with, as they can easily burn the operator's skin and eyes. Proper PPE (personal protective equipment) is required. Disposal is also tasking because both the used stripper and the water used to rinse the part are considered a hazardous waste and must be disposed of accordingly. Chemical strippers leave behind a perfectly smooth surface, so you may need to scuff up the surface before applying a new coating. This adds an extra step to the process. One exception would be if the surface was given a proper anchor profile before the original coating was applied.

Burn-off in oven also known as burn-off or bake-off or fluidized bed method uses very high temperatures to burn off powder coating, which turns to ash and must then be washed off.Thermal stripping is quite popular because it's one of the quickest ways to remove powder coating. It doesn't come with the same environmental concerns of chemical stripping.The extremely high temperatures required to remove powder coating may warp or damage parts. Like chemical stripping, this method does not leave an anchor profile which is critical for the reapplication of paint or coating.

Media blasting, abrasive blasting, which includes both traditional sandblasting and dustless blasting, uses media propelled at high speed towards the surface to strip off the powder coating. Dry blasting can take place in a blast cabinet or a blast room, whereas dustless blasting requires minimal or no containment. Traditional sandblasting can be a slow process for powder coating removal, and is not always favored. Because the dustless blasting process introduces water, it increases the mass and energy that the machine is putting out, making it dramatically faster than dry blasting. The water also cools the powder coat, making it brittle. This allows it to flake off as opposed to getting gooey, like it does with the heat generated from dry blasting because dustless blasting uses water to suppress the dust plume, the process is environmentally friendly and does not require bulky containment. This makes it perfect for blasting items that cannot fit into a blast cabinet, or cannot be moved.

Contact GZ Industrial Supplies for quality powder coating.

13th Nov 2020 Eze Obinna V.

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