The electrode potential of pure aluminum is -0.5 volts to negative 3 volts.
Although pure aluminum is an active metal, its stability is still quite high in many media, such as water, atmosphere, neutral solution, weak acid medium, and strong oxidizing medium.
This is because aluminum can form a dense continuous oxide film on the surface of aluminum in these media. This oxide film can protect aluminum from corrosion and influence of these media.
In the atmosphere, the oxide film formed on the surface of pure aluminum is very thin. This thickness is a function of temperature. At room temperature, the thickness is 2.5 microns to 5 microns, so aluminum is corrosion-resistant in the atmosphere.
The corrosion of pure aluminum and aluminum alloys is a very complex process, which is affected by environmental factors and is also related to the properties of aluminum alloys.
Among the factors affecting the environment, there are physical factors and chemical factors. The physical factors include temperature, movement, stirring, pressure, impurities, and stray current. The chemical factors include ingredients and impurities.
