Corrosion inhibition by aluminum oxide

Abstract

When metals and alloys come in contact with moisture and oxygen, they begin to decay. This process is known as corrosion. Corrosion is a natural, spontaneous, and thermodynamically favorable process. Corrosion cannot be completely eliminated, though the rate of corrosion can be controlled to some extent. We can postpone death, but we cannot stop death. There are many ways by which the rate of corrosion can be controlled. One such method is the use of inhibitors. These are chemicals that, when added in small quantities, arrest the rate of corrosion. There are many types of inhibitors based on many aspects. One such classification includes organic and inorganic inhibitors. They can be anodic type, cathodic type, or mixed type. There are many inorganic inhibitors such as phosphates, tungstates, vanadates, etc. Oxides of metals can also be used as corrosion inhibitors. Aluminum oxide is one such inhibitor. When aluminum undergoes corrosion, aluminum oxide is formed under certain pH values and electrode potential, as predicted by Pourbaix experiments. This aluminum oxide makes the metal immune. This acts as a protective layer. Water molecules and oxygen molecules cannot penetrate into this stable oxide layer. Thus corrosion is prevented. All these aspects are discussed in this chapter. A case study is also discussed, and various methods employed in corrosion of aluminum are also presented in this chapter. � 2022 Elsevier Inc. All rights reserved.