Means Of Protecting Metal Parts Against Corrosion

It is well known that humidity in the air induces corrosion to iron and steel elements. Corrosion starts from an inferior limit of 45-50% RH. If atmospheric humidity is below this value, steel will not be affected. Greater humidity leads to corrosion processes to start and the process will significantly accelerate between 60-100% RH. Free water around the steel means a corrosion process that is initiated quite fast.

If you need to store metal parts and are looking for a solution to protect against corrosion you must maintain atmospheric humidity at constant, low levels. Corrosion is not linked to temperature, only to humidity. Therefore what is important is that the air is dry, and this can be obtained by means of dehumidification.

Another way to protect against corrosion is to use cathodic protection. There are two possibilities for cathodic protection to be achieved. The sacrificial anode method implies coupling a carefully chosen metal (zinc, aluminum or magnesium alloys) to the metal that you want to protect against corrosion. What will happen is that, by acting as an anode, the metal that was selected will corrode instead of the one needing protection. The second possibility is to implement the impressed current method. The structure that you intend to protect against corrosion is connected to a current supply and a transformer rectifier ensures that the structure is provided with the required potential. Here is what you may need to protect against corrosion by using cathodic protection: water, gas or oil pipes that are buried or immersed, concrete structures that are reinforced, harbor installations and offshore platforms.

Using cathodic protection in combination with the use of a protective coating is more economical and efficient. The coating is the primary protection and the cathodic protection is the secondary one.

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