Katoodkaitses

Katoodkaitses refers to cathodic protection, an electrochemical method used to prevent corrosion of metal surfaces. This technique works by making the metal to be protected the cathode of an electrochemical cell. Corrosion is an electrochemical process where metal atoms lose electrons, becoming positively charged ions (oxidation). In cathodic protection, an external source of electrons is supplied to the metal, forcing it to gain electrons (reduction) and thus preventing it from oxidizing and corroding.

There are two primary types of cathodic protection systems. The first is sacrificial anode cathodic protection, which uses a more electrochemically active metal, such as zinc, aluminum, or magnesium, as a sacrificial anode. This anode corrodes preferentially, while the protected metal structure remains intact. The sacrificial anode is gradually consumed and needs to be replaced periodically.

The second type is impressed current cathodic protection. This system uses an external DC power source, like a rectifier, to force current from an inert anode (often graphite or a high-silicon cast iron) to the metal structure being protected. This method is typically used for larger structures like pipelines or ships where the current demands are higher. Both methods are widely employed in industries such as oil and gas, marine engineering, and construction to extend the lifespan of metallic infrastructure.