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Guidelines for Corrosion Prevention

Corrosion Management

Corrosion Prevention is crucial as degradation of the material is one of the most common reasons which render a material useless. Degradation can be divided into two categories, namely natural and artificial and the most common type of natural degradation is corrosion. It affects many different types of materials, like iron, zinc and galvanized metal, many of which are used as construction materials, machinery and articles of daily use. 

Corrosion, being an irreversible process, not only leaves the metal weak and brittle but also requires a significant expenditure in preventing it, so as to increase the life of the material.

Frequently Asked Questions- Corrosion Prevention

Metal corrodes when it reacts with another substance such as oxygen, hydrogen, an electrical current or even dirt and bacteria. Corrosion can also happen when metals like steel are placed under too much stress causing the material to crack.

A protective coating is a layer of material applied to the surface of another material with the intent of inhibiting or preventing corrosion. Materials used for metallic protective coatings include zinc, aluminium and chromium.

Lubricant are formulated with additives that form chemical bonds with the surfaces to prevent corrosion and rust. It reduces corrosion between two metallic surfaces and avoids contact between these surfaces to avoid immersed corrosion

There are 5 types of corrosion: Galvanic Corrosion, Uniform Corrosion, Pitting Corrosion, Erosion Corrosion and Selective Leaching.

It can severely affect the metals and makes them weaker. It can cause the metal parts to get stuck when they are supposed to slide over each other. This will affect the structural integrity of components. Similarly it will affects the machine life and aesthetics.

Types of Corrosion

Corrosion is described as any form of chemical and physical changes that can change the original properties of a substance leaving defeating the original motive of its use. All materials are prone to corrosion and in order to select the best anti-corrosion, we need to know the types of corrosion a metal undergoes.

Galvanic Corrosion

It is the degradation of a metal near the joints and happens when two electrochemically dissimilar elements are in contact in an electrolytic environment. This causes one of the metals to coat over another metal.

Uniform Corrosion

This type of corrosion usually happens in metals like iron where a different metal covers the surface of the original metal, gradually changing its properties like hardness or flexibility. It is the most benign and is accelerated by factors like moisture, temperature and exposure to air.

Pitting Corrosion

This type of corrosion starts from the surface of the metal, and causes small pits to be formed in the crust. This later develops into bigger holes and causes serious damage to the overall structure, the main damage is localised to a small area and thus being difficult to intercept.

Erosion Corrosion

This is caused by the flow of an erosive fluid that comes in contact with the metal surface, and thus causes an accelerated rate of corrosion.

Selective Leaching

This is the selective removal of one element by another from an alloy. They lead to processes like dealuminumification, decobaltification, etc.

Corrosion Prevention Techniques

While corrosion is an inevitable phenomenon, few corrosion prevention & protection techniques and some common tweaks can help you increase the longevity of the material.

Environmental Modification

Environmental factors like reactive gases, moisture, temperature causes an accelerated rate of corrosion. Therefore, keep the material in a dry atmosphere, well protected from reactive gases or metals that can come in contact.

Corrosion Inhibitors

Corrosion inhibitors are substances which react with the corrosive substances in the surrounding and thus maintain an inert atmosphere. They absorb themselves on the metal’s surface thus forming a protective film.

Cathodic Protection

This is done by converting the sites on metal needing protection to cathodic sites. This can be of two types, galvanic protection where an extra metal is introduced to sacrifice them to protect the metal, and impressed current where a DC current is applied to the electrolyte.

Corrosion Protection Coatings

Paints and other coatings are used to protect metal from degradation. They include two-part urethane, high solid coating, powder coating, etc.

Corrosion as a phenomenon cannot be ignored but can be surely prevented. For that, you need to do a detailed research of metal and types before prevention steps are taken.

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