There are various combinations of causes for rust formation, and accordingly, there are various means to prevent it. Broadly speaking, these can be divided into preventive measures and remedial measures. The former refers to taking action before rust occurs, which is included in the initial costs. The latter refers to taking action after rust has occurred, which is included in the running costs. When categorized by principle, the methods of rust prevention are illustrated as shown in the right diagram. The initial categories A to C refer to natural environments, while D represents contact with artificial environments or aqueous solutions. 1) Laissez-faire: A method based on the premise of replacement after a certain period. 2) Material design: A method of developing materials with enhanced corrosion resistance considering the usage environment. 3) Structural design: A method that takes into account the occurrence of gaps and contact between dissimilar metals. 4) Surface treatment: A method of plating metals such as zinc and aluminum. 5) Coating: A method of covering the surface with organic materials. 6) Environmental treatment: A reliable method to suppress rust formation through drying and air purification. 7) Electrolytic protection: A method of maintaining the electrode potential of steel below a certain level.

What does it mean for metals to rust in the first place? Generally, the phenomenon of "rusting" refers to metals releasing electrons and becoming ionized. In other words, this is called "oxidation." Additionally, there is a paired term for "oxidation," which is "reduction," and oxidation and reduction occur through the transfer of "electrons." What forms on the surface of metals due to this phenomenon is commonly referred to as 'rust.' There are several types of 'rust,' with the most well-known being iron rust. Iron rust has several common names depending on its state. Next, a well-known type is verdigris. This is a green rust that forms from the oxidation of copper, and there is also zinc rust, which is referred to as white rust. Thus, even though we refer to it simply as 'rust,' there are various types, and many colors and properties exist. There may even be types of 'rust' that have yet to be discovered. However, the phenomena of 'rusting' and 'oxidation' are singular, so it is sufficient to take measures according to the situation.