Some metals corrode badly on contact with air and water. This means that the surface of the metal reacts with oxygen to form an oxide. The metal loses its shine as a layer of oxide covers it. This is sometimes known as tarnishing. When a bowl covered with silver is cleaned, for example, what is really happening is that the layer of tarnish is being rubbed away. Over a long period of time, all the silver may be rubbed off. Iron corrodes in air and water to produce rust. Non-reactive metals are less likely to corrode than reactive ones.
Corrosion is a natural process that involves the deterioration of metal components. According to NACE International, corrosion is “the destruction of a substance (usually a metal) or its properties because of a reaction with its environment.” This ultimately causes potentially severe damage to your building or application and can become very costly to repair.
Corrosion is an electrochemical reaction that appears in several forms, such as chemical corrosion and atmospheric corrosion, the latter of which is the most common form. When acidic substances (including water) come in contact with metals, such as iron and/or steel, rust begins to form. Rust is the result of corroding steel after the iron (Fe) particles have been exposed to oxygen and moisture (e.g., humidity, vapor, and immersion). When steel is exposed to water, the iron particles are lost to the water’s acidic electrolytes. The iron particles then become oxidized, which results in the formation of Fe??. When Fe?? is formed, two electrons are released and flow through the steel to another area of the steel known as the cathodic area.
Oxygen causes these electrons to rise up and form hydroxyl ions (OH). The hydroxyl ions react with the FE?? to form hydrous iron oxide (FeOH), better known as rust. Where the affected iron particles were, has now become a corrosion pit, and where they are now, is called the corrosion product (rust). Corrosion can happen at any rate, depending on the environment that the metal is in. However, since atmospheric corrosion is so widespread, it is recommended to take effective precautionary measures when it comes to corrosion prevention.
Depending on the situation and application, you may be able to treat the area that has corroded. If the affected area is small and treatable, you may require some tools and products to remove it. Begin by removing the rust from the metal using tools such as a grinding wheel or needle gun. Be careful not to cause any additional damage to the metal. For large corroded areas, you may want to consider a permanent protective coating, such as CSL’s SI-COAT Anti-Corrosion Protective Coating. You will also want to take this time to look at the application as a whole for other premature signs of corrosion.
The Golden Gate Bridge in San Francisco needs to be painted regularly to stop it from corroding.
Picture Credit : Google
