anodic

Anodic (from anode) is a term used in electrochemistry to describe processes, electrodes, or conditions associated with the anode, the electrode at which oxidation occurs. In electrochemical cells the designation depends on the cell type: in galvanic (voltaic) cells the anode is the electrode that loses electrons and is the negative terminal; in electrolytic cells, where an external power source drives the reaction, the anode is the positive electrode.

Anodic reactions include the oxidation of species at the anode, such as metal dissolution (M → M^n+ + ne−) or the formation of oxide films on metals during anodic oxidation. A common applied example is anodizing aluminum, a controlled electrochemical process that grows a thin, typically protective oxide layer that improves corrosion resistance and enables coloring. Similar anodic oxidation is used for titanium, zinc, and other metals.

Anodic protection is a corrosion-control technique in which a metal structure is maintained at an anodic potential by external current to sustain a protective oxide; this approach is used for pipelines and tanks in aggressive environments.

Anodic processes are contrasted with cathodic ones, where reduction occurs. The adjective anodic is used in contexts ranging from corrosion science to materials treatment and electroplating.