Elektrokorrosion

Elektrokorrosion, also known as galvanic corrosion, is an electrochemical process that occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte. This situation creates a galvanic cell, where the more active metal (anode) corrodes preferentially, while the less active metal (cathode) is protected. The driving force for this corrosion is the difference in their electrochemical potentials.

The electrolyte, which can be water, soil, or even atmospheric moisture, acts as a medium for ion flow, completing the electrical circuit. The anode metal oxidizes, losing electrons, which then travel through the metallic connection to the cathode. At the cathode, these electrons are consumed in a reduction reaction, often involving the reduction of oxygen or hydrogen ions. This process leads to the accelerated degradation of the anodic material.

The rate of elektrokorrosion depends on several factors, including the difference in electrochemical potential between the two metals, the resistivity of the electrolyte, the surface area ratio of the cathode to the anode, and environmental conditions such as temperature and the presence of corrosive species. Common examples include steel fasteners in contact with aluminum alloys or copper pipes connected to galvanized steel. Understanding elektrokorrosion is crucial in material selection and design to prevent premature failure and ensure the longevity of structures and components. Mitigation strategies often involve separating dissimilar metals with insulating materials or using cathodic protection techniques.