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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 involves taking countermeasures before "rust" occurs, which is included in the initial cost. The latter involves taking countermeasures after "rust" has occurred, which is included in the running cost. When showing rust prevention methods by principle, it looks like the diagram on the right. The initial 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, involving drying and air purification. 7) Electrolytic protection: A method of keeping the electrode potential of steel below a certain level.

What does it mean for metal to rust in the first place? Generally, the phenomenon of "rusting" refers to the process by which metal releases electrons and becomes ionized. In other words, this is called "oxidation." Additionally, there is a term "reduction" that is paired with "oxidation," and both oxidation and reduction occur through the transfer of "electrons." The substance that forms on the surface of the metal due to this phenomenon is commonly referred to as "rust." There are several types of rust, and the most well-known is probably 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 occurs when copper oxidizes, 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 not yet been discovered. However, the phenomena of "rusting" and "oxidation" are singular, so we can take measures according to the specific situation.