Abstract: An aluminum nitride substrate which is or forms part of a device, is coated on an upper side with a diamond layer. On a lower side of the substrate includes a coated area with a carbon-based coating containing at least 50% sp2 configured carbon. Also on the lower side is a free area which has a thinner carbon-based coating than is positioned in the coated area. The free area covers at most 10% of the lower side of the substrate and may be formed from a plurality of partial areas. Either or both the upper side or lower side of the substrate may include a structural element such as an elevation or a depression.

Abstract: An electrode for an electrochemical reaction bath has a base body, an active side which is configured to come into contact with the reaction bath, and a passive side which is configured to come into contact with at least one electrical conductor. The passive side includes a doped carbon coating that is preferably less than 5 ?m in thickness. Preferably the doped carbon coating is a doped polycrystalline diamond coating in sp3 configuration and is doped with boron.

Abstract: An electrode for an electrochemical reaction bath has a base body, an active side which is configured to come into contact with the reaction bath, and a passive side which is configured to come into contact with at least one electrical conductor. The passive side includes a doped carbon coating that is preferably less than 5 ?m in thickness. Preferably the doped carbon coating is a doped polycrystalline diamond coating in sp3 configuration and is doped with boron.