The corrosion of aluminum alloy door and window hardware is a chemical reaction and electrochemical reaction process, as well as a variety of substances and forms of reaction. However, the main cause of corrosion damage of aluminum alloy door and window hardware is electrochemical corrosion under natural conditions. Aluminum alloy doors and windows are composed of aluminum, stainless steel, zinc alloy, carbon steel and so on. These metals with different electrode potentials and contact each other constitute galvanic cells in corrosive substance, thus causing electrochemical corrosion.
There are three environmental factors causing corrosion of aluminum alloy doors and windows
Because the water in the air condenses into liquid water film is the necessary condition for forming corrosion galvanic cell, so the humidity of air is the main factor. When the humidity reaches a certain critical value, water film forms on the surface, and the corrosion rate increases.
When the temperature is high and humidity is high, the corrosion is accelerated. When the temperature changes abruptly from high temperature, the water vapor in the atmosphere condenses into a film, which can also accelerate the corrosion process. The longer the damp time, the more serious the corrosion. Generally speaking, when the temperature difference between day and night is greater than 6 ℃ and the temperature changes in the range of 5 ℃ - 50 ℃, as long as the relative humidity reaches 65% - 75%, condensation will appear.
3. Air pollution
Under normal circumstances, there are few corrosive media in the air, only oxygen corrodes metal frequently. However, with the continuous development of industrial enterprises, harmful gases and dust in the air increase greatly, such as carbon dioxide, sulfur dioxide and other gases generated after the combustion of coal, kerosene and diesel oil, as well as a large number of dust, such as smoke, coal ash, chloride and other acid, alkali and salt particles Some of them are corrosive in nature, others are coagulated in water droplets and have corrosive effect on metals.