Corrosion refers to the gradual wear-and-tear and destruction of metal. While it is a natural event that occurs due to reactions with the surrounding environment, it can severely compromise the aesthetics and functionality of metal products.
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The most common type of corrosion is rust, which occurs as a result of moist air coming in contact with iron to create hydrated ferric oxide. Pure gold does not corrode, but silver, bronze, and other similar metals can “tarnish”—which means that a thin layer of corrosion forms on the base metal. Galvanized products (iron or steel products coated with a protective layer of zinc) also corrode, but they do so at a slower pace if the galvanized coating is still intact.
Now that you have a basic understanding of corrosion, how do you keep it from happening? Below we look at some of the most common prevention methods.
1. Regulate the Environment
Several environmental factors increase the odds of metal corrosion. By keeping the metal in a clean, dry space when it isn’t needed, the appearance of rust can be minimized. Also, taking steps to reduce the oxygen, sulfur, and chlorine content in the environment can slow down the pace of metal deterioration. For instance, when it comes to a hot water heater, you can use softeners to treat feed water to modify the oxygen content or alkalinity. This will reduce the risk of the unit’s interior corroding.
2. Apply Protective Coating
This can offer a layer of safety against rusting by acting as a barrier between the oxidizing components in the environment and the metal parts. A frequently used protective coating method is galvanization, where manufacturers use a fine layer of zinc to cover the part. Another viable option for preventing corrosion on metals is powder coating. With the right approach, powder coating can conceal the part’s surface away from the external elements to safeguard against corrosion.
3. Leverage Cathodic Protection
Cathodic protection converts unnecessary anodic sites on the surface of the metal to cathodic sites by using an opposing current. The most commonly used method of cathodic protection involves the use of galvanic anodes. The process utilizes metal anodes that sacrifice themselves in order to keep the cathode safe from external factors. These sacrificial anodes are typically made of magnesium, zinc or aluminium. However, it’s not uncommon for manufacturers to switch between galvanic anodes and cathodic protection. The latter is where a current’s negative terminal is linked to the metal and the positive terminal is linked to an auxiliary anode for completing the circuit.
4. Control Rusting at the Engineering Stage
If metal is going to be used in an environment where it’s susceptible to corrosion, makers should build the part with that knowledge in mind. For instance, metal parts that are exposed to environmental elements should enable debris and water to drain off instead of gathering on the surface. Similarly, narrow gaps that allow fluid or air to enter should be eliminated to prevent crevice corrosion. For environments that are corrosive by nature, like saltwater, it could be a good idea to manufacture for a certain extent of rusting.
5. Invest in Inhibitors
Inhibitors refer to the chemicals that react with the environmental gasses or the surface of the metal to disrupt the chemical processes that lead to corrosion. They work by absorbing themselves on the surface of the metal to create a protective film. Users can apply them as a protective coating or as a solution through dispersion methods. The pace at which an inhibitor slows down corrosion depends upon the uptick of the electrical resistance on the surface or the reduction in the ions’ diffusion to the surface. Another benefit of inhibitors is that they can be utilized as a corrective action to mitigate sudden corrosion.
6. Consider Alloyed Steel
Alloyed steel is one of the best ways to keep corrosion at bay. It combines the components on several metals to deliver added resistance and strength to the item in question. Nickel that is corrosion resistant can be mixed with oxidation-limiting chromium to create an alloy that can be utilized in reduced and oxidized environments. Varying alloys offer resistance to different environments, giving stakeholders enhanced flexibility. However, alloyed steel isn’t practical in terms of cost. Manufacturers with limited budgets will need to adopt other tactics.
7. Keep Tabs on Surface Health
Monitoring the health of the metal’s surface is also crucial for protecting it against potential corrosion. Asperous surfaces, crevices or cracks, whether a by-product of design flaws or wear and tear, can result in higher rates of rusting. Adequate monitoring and the removal of unwanted surface conditions is an effective part of corrosion prevention. In addition, makers can take steps to ensure that corrosive elements are not used in the maintenance or cleaning of metal parts and that reactive combinations of metal are avoided.
This is a process that leverages a positively charged metal to cover a base metal that’s negatively charged. However, electroplating requires a power source and cannot happen naturally. It enables manufacturers to create items with cost-friendly base metals, then use high-quality metals to provide the required coating. If they are to engineer products that feature only high-quality metals, they’ll need to raise a lot more capital. Electroplating, on the other hand, is wallet-friendly. Aside from minimizing corrosion, electroplating can be used to eliminate friction, enhance aesthetics, make objects less prone to wear and tear, and assist conductivity.
Choosing the ideal corrosion resistance method for your metal isn’t straightforward. While the recommended solution is to manufacture the metal according to the environment, it is not always feasible to disrupt the design processes. In situations like these, electroplating and other corrosion-preventing measures come in handy.
Additionally, you can take steps to keep the environment where the metals are being manufactured free of humidity. Doing this enhances the moisture inside the air and could set up the tools to encounter potential corrosion. If your facility has a lot of humidity, try getting a dehumidifier to make the surroundings less rust-friendly. This is particularly useful if you have large equipment that is difficult to seal or move.