ã€China Aluminum Industry Network】Generally speaking, the corrosion of aluminum alloy door and window hardware is a chemical reaction and electrochemical reaction process, and it is also a variety of substances in a variety of forms of reaction, it is difficult to explain with one or two reaction modes. However, the cause of rust damage to aluminum alloy door and window hardware is mainly electrochemical corrosion under natural conditions. Aluminum alloy doors and windows are generally composed of aluminum, stainless steel, zinc alloy, carbon steel, etc. These metals with different electrode potentials in contact with each other constitute the primary battery in the corrosive substances, thereby causing electrochemical corrosion. Especially in the marine atmosphere and industrial atmosphere, the material structure of aluminum alloy doors and windows determines the necessity of electrochemical corrosion. Among them, the aluminum alloy profile is easy to be passivated, and the potential relative to other materials is changed from negative to positive to slow or stop the corrosion, and steel parts with a relatively negative potential will increase corrosion and cause damage to the hardware.
Meteorological factors 1. Humidity As the condensation of water in the air into a liquid water film is a necessary condition for the formation of a corrosive primary battery, the humidity of the air is the main factor. When the humidity reaches a certain critical value, a water film forms on the surface and the corrosion rate increases.
2. When the temperature is high temperature and high humidity, the temperature rises and accelerates corrosion. When temperature changes suddenly drop from high temperature, condensation of water vapor in the atmosphere can form a film, which can also accelerate the corrosion process. The longer the wet time, the more severe the corrosion. Generally speaking, the temperature difference between day and night is greater than 6°C. When the temperature changes within the range of 5°C to 50°C, as long as the relative humidity reaches 65% to 75%, fogging will occur.
3. Atmospheric pollution Under normal conditions, there are few corrosive media in the air, and only the corrosion of oxygen by metals is common. However, with the continuous development of industrial enterprises in various countries, harmful gases and dust in the air have also increased substantially, such as coal. Gases such as carbon dioxide and sulfur dioxide generated after the combustion of kerosene and diesel oil. There are also a lot of dust, such as smoke, coal ash, chlorides and other acids, alkalis, salt particles, etc. are also dispersed into the atmosphere, and some of them are corrosive, and some are contaminated in the water droplets have a corrosive effect on the metal.
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