March 06, 2020 2 min read

Hard anodizing, as it pertains to aluminum, is a process that gives the metal some great added advantages while still allowing it to retain its basic advantages. Hard anodized aluminum is more heat resistant, improved wear resistance, and is even more resistant to corrosion.

How Is It Done?

When you anodize aluminum, the process creates what is called aluminum oxide. This hard-anodized aluminum coating is applied using a unique electrolytic process that creates a hard layer of aluminum oxide that not only lies on the surface of the aluminum but in the aluminum as well. 

Regular vs Hard Anodizing

There are a few differences between both hard and regular anodizing, and hard anodizing is an exceptionally strong and more durable form of anodized aluminum that is usually much thicker and requires a different process from the standard anodized aluminum. 

Why is it Used?

Because of growing industries such as the aerospace, appliance, military and fire fighting markets, hard anodizing continues to develop in the number of applications. Processes and applications are available for things such as cylinders, pistons, gears, and plenty of other mechanical parts that can be prone to wearing out over time. 

Advantages of Hard Anodizing

Hard anodizing has many different benefits, such as the wear resistance that it offers. Hard anodized coatings are more than 10 times more resistant to continuous wear than regular anodized aluminum. Hard anodized aluminum is extremely hard, and hardness microhardness tests will usually show results of 500 to 530 VPN. On top of being even harder, the hard anodizing process gives the aluminum better thermal properties. It is resistant to greater temperatures, even up to 2000 degrees, and has very low thermal conductivity or expansion.

Hard anodized coatings are extremely corrosion resistant, and can usually pass the 1000 hour 5% salt spray test. It is also excellent at being an insulator for electricity and having great electrical resistance, being nearly as good as things like glass or porcelain.


Hard anodized aluminum continues to grow in popularity every single year and for good reason. If something needs to be more heat resistant, wear-resistant, or more resistant to wear, the hard anodizing process can help solve the problem!

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