There are three types of corrosion that can affect aluminum most often. Those types include crevice corrosion, galvanic corrosion and pitting. However, it is possible to prevent corrosion through design, which is why many manufacturers of parts, products and components choose to extrude aluminum and alloys instead of using other methods. Custom aluminum extrusion is achieved through the design of specialty dies or profiles to create a desired shape. By working with an experienced designer, such as the team at Silver City Aluminum, it is possible to achieve even greater results through the use of aluminum industry solutions to create even more resistant parts.
Naturally Resistant to Corrosion
The first thing you need to know about aluminum is that it is naturally resistant to corrosion. Even in its natural, untreated state, rod and bar aluminum or specialty designed aluminum has a very good resistance to corrosion in most environments. Aluminum is a metal that has the ability to form a very thin, yet extremely effective, oxide layer to prevent oxidation or corrosion. This oxide layer is impermeable and adheres very strongly to the aluminum itself. Another special trick is that if this oxide layer were damaged in some way, it can repair itself!
- CREVICE – This type of corrosion occurs in narrow crevices that are typically filled with liquid, such as water. When you extrude aluminum alloys to create rod and bar aluminum or custom shapes, this type of corrosion is not very common. However, if the parts, products or components are used in a marine atmosphere where there is constant water or salt in the air, the likelihood increases. Rain water or condensation can pool into crevices and cause corrosion, however for parts that will be used in areas exposed to the outdoors or where water is present, aluminum industry solutions, such as custom profiles or dies, can prevent corrosion through design.
- GALVANIC – When there is contact with metal and an electrolytic bridge between two different metals, galvanic corrosion can occur. When two metals are touching, the metal that is the “least noble” will be the one that becomes the anode and experiences corrosion. The “most noble” metal becomes the cathode and is then protected against corrosion. When combined with most other metals, aluminum is typically the “least noble” metal, making it more at risk for developing a galvanic corrosion than other types of materials, such as copper, stainless steel or carbon steel. Galvanic corrosion will not occur in a dry indoor space, however in areas that are near the ocean, high chloride levels could initiate the corrosion.
- PITTING – The most common type of corrosion that affects aluminum is pitting. This occurs when an electrolyte, such as water or moisture that contains dissolved salts, is present. It is called “pitting” because this type of corrosion is typically revealed in small pits that can completely penetrate the thickness of the metal, especially if exposed to open air, water or soil. While pitting is more of an aesthetic issue, it can and still should be prevented if the risk for corrosion is high. Surface treatment through powder coating, anodizing or painting can be done to treat and protect the aluminum, as well as better designs that can prevent corrosion from happening in the first place. Keeping the rod and bar aluminum or other shaped parts should be kept clean and dry to prevent pitting and aluminum industry solutions can prevent corrosion through design by reducing the amount of angles and pockets in the shape, which could collect water.
If you are in the market for aluminum industry solutions in the form of parts, products and components, contact Silver City Aluminum. Our team is dedicated to providing each client with the top standards of quality and service to offer superior custom aluminum products that will exceed expectations. We place our focus on the application of the product, to consider all aspects of its intended use. This helps us to design top quality custom aluminum extrusions, as well as standard extrusions, such as rod and bar aluminum, tubing and more.
We work with each client to create smart profiles that help to prevent corrosion through design and create a finished product that will meet their requirements. We work continually to improve quality control and provide top notch customer service. Call us today for a FREE estimate on your next project. You can reach us at our Taunton, MA office by dialing 508-542-7200 or use our convenient online contact form.