An electrochemical and optical study of the rupture and restoration of the passivating HgO multilayer on a dropping mercury electrode in aqueous 1 M NaOH solution at anodic potentials
It is shown that the passivating layer on the surface of a dropping mercury electrode in 1 M NaOH at anodic potentials due to drop growth continuously is being mechanically ruptured and electrochemically repaired. This phenomenon is studied by means of microscopy, reflectometry and polarography. The latter technique allows current spikes to be measured. The relation between faradaic current during such a spike and time is discussed.
The present invention provides a sealing liquid which does not contain a nickel salt but is capable of achieving a sealing performance equivalent to that in cases where a sealing liquid containing a nickel salt is used, and which enables an anodic oxide coating film sealed therewith to exhibit excellent contamination resistance. ::: The present invention provides a sealing liquid for anodic oxide coating films of aluminum alloys, which contains a metal salt, a pH buffering agent and a surfactant, and which is characterized in that the metal salt is at least one salt selected from among alkali metal salts and alkaline earth metal salts.