| abstract |
Electrodes for electrochemical processes, especially anodes for the cathodic protection of metal substrates, e.g. reinforcing bars in concrete, comprise a conductive core which acts as a current-distributing member, an outer member which provides an electrochemically active outer surface, and an intermediate member composed of a material which is of higher resistivity, and/or which is less electrochemically active, than the material of the outer member. The higher the resistivity of the intermediate member, the more regular the current distribution along the length of the electrode. When the intermediate member is less electrochemically active, this protects the core from corrosion if the outer member is damaged by physical means or through electrochemical erosion. Preferably at least one of the intermediate member and the outer member is composed of a conductive polymer, especially one comprising carbon black or graphite as conductive filler. |