Corrosion

Corrosion is the process of deterioration of materials, usually metals, as a result of chemical or electrochemical reactions with their environment. It is a natural process that can be influenced by various factors such as moisture, oxygen, and other environmental conditions.

Causes of Corrosion

• Moisture: Water or humidity can accelerate the corrosion process.
• Oxygen: Presence of oxygen in the environment can cause oxidation of metals, leading to corrosion.
• Acids and Bases: Chemical substances with acidic or basic properties can corrode metals.
• Salt: Exposure to salt, such as in seawater or road salt, can accelerate corrosion.

Types of Corrosion

Corrosion can manifest in various forms, including:

• Uniform Corrosion: Generalized corrosion that occurs evenly across the surface of the metal.
• Galvanic Corrosion: Occurs when two different metals are in contact in the presence of an electrolyte, leading to accelerated corrosion of one of the metals.
• Pitting Corrosion: Localized corrosion that results in the formation of small pits on the metal surface.
• Crevice Corrosion: Occurs in confined spaces such as gaps and crevices where the access of oxygen and moisture is limited, leading to localized corrosion.
• Stress Corrosion Cracking: Occurs due to the combined influence of tensile stress and a corrosive environment, leading to cracking of the metal.

Prevention and Control

Corrosion can be prevented or controlled through various methods, including:

• Protective Coatings: Applying paints, varnishes, or specialized coatings to create a barrier between the metal and the environment.
• Galvanization: Coating the metal with a layer of zinc to provide sacrificial protection.
• Alloying: Mixing metals to form alloys that are more resistant to corrosion than pure metals.
• Cathodic Protection: Using sacrificial anodes or impressed current to protect the metal from corrosion.
• Proper Maintenance: Regular inspection, cleaning, and maintenance of metal surfaces to prevent corrosion.

Study Guide

Here are some key points to remember when studying corrosion:

1. Define corrosion and explain its significance in everyday life.
2. Identify the factors that contribute to corrosion.
3. Describe the different types of corrosion and their characteristics.
4. Explain the methods used to prevent and control corrosion.
5. Discuss real-life examples of corrosion and its impact on various industries.