Tank Anodization Can Offer More than Corrosion Protection

Combating corrosion is an ongoing battle for many plant managers working alongside industrial tanks. One line of defense is to anodize your metal tanks and piping for added protection. Applying this electrochemical process helps seal many types of metals, primarily aluminum alloys, in a way that makes them much more resistant to corrosion.

Getting technical

The anodization process begins by immersing metal in an electrolytic solution tank with a cathode, or a negatively charged electrode, that introduces electrons into the solution. When the current passes through the bath, a hydrogen solution is released from the cathode and oxygen collects on the anode, or the positively charged section. This creates a metal oxide film on the metal submerged in the tank, effectively anodizing it. The film changes the metal’s exterior and its crystal structure, making it stronger and more resistant to degradation.

Understanding the value

Anodized metal alloys are much sturdier and more resilient than untreated metals. The anodized finish lasts indefinitely and is much more durable and resistant to damage at the hands of corrosion or abrasion. It’s an inexpensive solution that also happens to be environmentally friendly. Anodizing industrial metal storage tanks is especially valuable because it better equips the metal to withstand the harsh and often caustic environments it’s inherently used in. There are many ways to anodize metal, but three common methods include:

1. Chromic acid anodizing — This process, also known as Type 1, “was used in the first commercial anodizing facilities in the 1920s.” It requires a chromic acid based chemical bath. Chromic acid anodizing creates a thin protective oxide layer on the metal, which can provide atmospheric protection for corrosive environments.
2. Sulfuric acid anodizing — This process, also known as Type II, is the most common anodizing process. Known for their durability and strength, sulfuric acid coats offer thicker layers of protection from abrasive and corrosive materials. These coatings often have a thickness between 0.1 and 1.0 mil.
3. Hard coat anodizing — This process is also known as Type III anodizing. According to the Aluminum Anodizers Council FAQ sheet, this process entails “sulfuric acid or mixed chemistry electrolytes” and creates an even harder and more abrasion resistant layer on the metal. The hardcoat is a strong protectant that helps uphold metal integrity among caustic materials.

Depending on the final use of the anodized metal, it might be best to repeat the process to ensure the protective film is thick enough to function well in nearly any environment. Anodizing metal tanks can offer many benefits, including a safer facility and employees. By increasing tank durability, you can reduce the odds of potentially dangerous leaks and spills. Anodization also helps reduce maintenance downtime and associated costs by increasing the system’s longevity, protecting your surroundings and your investment. Further, anodizing tanks can result in greater color stability and aesthetics. Ready to make the worthwhile investment in your plant?