(1) The relative humidity of the atmosphere is the percentage of the water vapor content and its saturation content at the same temperature. Below a certain relative humidity, the rate of metal corrosion is very small, but above this relative humidity, the rate of corrosion increases sharply. This relative humidity is called critical humidity. The critical humidity of many metals ranges from 50% to 80%, while that of steel is about 75%. The relative humidity of the atmosphere has the greatest impact on metal corrosion. When the atmospheric humidity exceeds the critical humidity, a water film or water droplet appears on the metal surface. If harmful impurities contained in the atmosphere dissolve in the water film or water droplet, it becomes an electrolyte, exacerbating corrosion.
(2) The correlation between temperature and humidity affects the corrosion of metal buttons. There are some main situations as follows: firstly, the water vapor content in the atmosphere increases with the increase of temperature; Secondly, high temperatures exacerbate corrosion, especially in humid environments where the higher the temperature, the faster the corrosion rate. When the relative humidity is low, the effect of temperature on corrosion is not very obvious, but when it is above the critical humidity, the amount of corrosion increases sharply as the temperature increases. Chicken eye manufacturers remind us that if there is a temperature difference between the atmosphere and the metal, condensation water can form on the surface of the metal at low temperatures, which can also lead to metal rust.
(3) Corrosive gases pollute the air, with sulfur dioxide having the greatest impact on metal corrosion, especially on copper and its alloys. Sulfur dioxide in the atmosphere mainly comes from the combustion of coal. At the same time, the combustion product carbon dioxide also has a corrosive effect. There are corrosive gases mixed in the atmosphere around the factory. Factors such as hydrogen sulfide, ammonia, and hydrochloric acid are all factors that promote metal corrosion
(4) Other factors include a large amount of dust in the atmosphere, such as smoke, coal ash, chlorides, and other acid, alkali, and salt particles. Some of them are inherently corrosive, or are condensation nodules of water droplets, which are also corrosion factors. For example, chlorides are considered the "deadly enemies" of corrosive metals
