What is the cause of corrosion of aluminum plate?

      Pitting Corrosion, also known as pitting corrosion, is a localized form of corrosion that produces pinpoint, point, and hole shapes on the metal. Pitting corrosion is a unique form of anodic reaction and is an autocatalytic process, that is, the conditions created by the corrosion process within the pitting pores are both conducive and sufficient to sustain the continuation of corrosion.

     Uniform corrosion The oxide film on aluminum will dissolve in solutions such as phosphoric acid and sodium hydroxide, resulting in uniform corrosion and uniform dissolution rate. The temperature of the solution increases and the concentration of the solute increases, which promotes the corrosion of aluminum.

     Crevice Corrosion Crevice corrosion is a localized corrosion. In the electrolyte solution of metal parts, due to the formation of gaps between metals and metals or between metals and non-metals, the width is sufficient to allow the medium to be immersed and the medium is in a stagnant state, which makes the internal corrosion of the crevice aggravated.

     Stress Corrosion Cracking (SCC) SCC of aluminum alloys was discovered in the early 1930s. A kind of damage that occurs in metal under the combined action of stress (tensile stress or internal stress) and corrosive medium, which is called SCC. SCC is characterized by the formation of corrosion-mechanical cracks that can either develop along grain boundaries or propagate through grains. Since the crack propagation is inside the metal, the strength of the metal structure will be greatly reduced, and sudden damage will occur in severe cases. SCC will occur under certain conditions, they are: – a certain tensile stress or residual stress inside the metal.