cathodische

Cathodische is an adjective used in Dutch and German to denote a relation to the cathode in electrochemistry and related fields. The term is derived from the word cathode, which itself comes from the Greek katodos, meaning “downward way,” referring to the electrode where reduction takes place in an electrochemical cell.

In electrochemistry, cathodische processes refer to reactions occurring at the cathode, typically reductions such as uptake of electrons by ions or molecules from the solution. This is contrasted with anodische processes, which occur at the anode and involve oxidation. In galvanic or electrolytic cells, the direction of current and the naming of electrodes depend on the convention of electron flow or conventional current.

Cathodische protection (often rendered “cathodic protection” in English) is a practical application in corrosion control. It uses either sacrificial anodes (more reactive than the protected metal) or an impressed current from an external power source to make the protected surface the cathode, thereby suppressing corrosion. Common applications include steel pipelines, offshore platforms, ships hulls, and buried or submerged structures. Correctly applied, the method shifts the electrochemical potential of the metal surface to a value that inhibits anodic dissolution.

In material science and surface engineering, cathodische properties may also refer to characteristics arising from cathodic polarization, such as changes in surface chemistry, hydrogen evolution, or passivation behavior of metals like steel, copper, or aluminum. Hydrogen evolution at highly cathodic potentials can lead to hydrogen embrittlement in high-strength steels.