Atmospheric corrosion of aviation aluminum alloys is affected by many factors, mainly due to atmospheric factors such as temperature, rainfall, biological and atmospheric pollutants. The influence of these factors is different, and it will change with the change of geographical and temporal conditions, and the factors are related.
The formation of water film on the surface of aerospace aluminum alloy is the basic condition for atmospheric corrosion. The formation of water film is one of the most important factors affecting the atmospheric corrosion of metal materials. The longer the wetted surface of the aviation aluminum alloy, the greater the amount of corrosion. On the one hand, the rainfall in the atmosphere increases the relative humidity in the atmosphere, prolongs the hydration time, scouring destroys the protection of corrosion products, accelerates metal corrosion, and on the other hand, the dirt and dust corrosion of the metal surface washed away by rain is slowed down.
The temperature affects the condensation of water vapor on the metal surface, the solubility of various corrosive gases and salts in the water film, the resistance of the water film, and the reaction rate of the anion and anode processes in the corroded battery. The effect of temperature should be considered in combination with the relative humidity of the atmosphere. When the relative humidity is low and the critical relative humidity of the metal is low, the effect of temperature is very obvious.
Three solid dust particles
There are generally three cases of the effect of solid dust particles on the atmospheric corrosion of metal materials: First, soluble and corrosive dust particles are dissolved in the night magic called corrosive medium, which increases the corrosion rate; second, the dust particles themselves have no corrosive properties and do not dissolve. However, it can adsorb corrosive substances. When it is dissolved in the water film, it promotes the corrosion process. Thirdly, it is non-corrosive and adsorbable. If it falls on the metal panel, it may be a gap between the sand and the metal surface, which is easy to form moisture. Localized corrosion occurs. The main components of the atmosphere in the world are basically unchanged. According to the different natures and degrees of pollutants in different environments, the nature of the atmosphere can be roughly divided into industrial atmosphere, ocean atmosphere and city. Atmosphere and rural atmosphere, but there is no quantitative wiring between them