8/14/2023 0 Comments Does aluminium rust![]() For a fresh surface-treated aluminum in the atmosphere is not contaminated, this threshold is about 66 % (drawing 1.2). This is because, that lacks moisture in low humidity, to create a continuous electrolytic film on the metal surface. There is a critical threshold for the relative humidity, below which aluminum and its alloys do not corrode. The critical relative humidityĪtmospheric corrosion of metals, including, aluminum, It occurs in thin films of moisture, which are arranged on the metal surface. Under these conditions at the metal surface can occur moisture condensation. moistening duration typically determined, as the time, during which the relative humidity exceeds 80 % and, in the same time, on the metal surface temperature is higher 0 oC. Lasting moisturizing called period, during which sufficient moisture on the surface of the metal to corrosion. Duration moisture and sulphate electrolyteĬorrosion metals outdoors depends on the so-called wetting length and chemical composition of the electrolyte surface. For a given level of humidity is the temperature, to which air must be cooled, to become saturated with moisture, and started her falling on nearby surfaces. ![]() The dew point is the temperature, at which moisture condensation will start. During the shower, it can reach 90-95 %, and during the tropical rains approach 100 %. In deserts and the arid zones of the relative humidity level seldom exceeds 10-20 %, whereas it is found mostly in temperate climates between 40 and 60 %. saturated with moisture, if the relative humidity of about 100 %.wet, if the relative humidity is higher 80 %.normal, if the relative humidity is between 50 to 60 %.dry, if the relative humidity is not more than 30 %.This ratio is expressed as a percentage.Īt normal room temperature, air is considered: Relative humidity - the ratio between the actual water vapor pressure and a maximum pressure of water vapor at a given temperature. Rain is one, but not the only factor, which determines the relative humidity. The rate of atmospheric corrosion is dependent on relative humidity, and not just on the number or intensity of rainfall in the area. These factors can also have the opposite effect: rain increases the humidity in the air., but also washes away dust, and corrosion products, which may reduce the corrosion rate relative humidity for instance, hung air contamination may reduce the critical value of the relative humidity, at which corrosion begins to develop. ![]()
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