Effects of silicone oil additives on hydrogen adsorption and tunnel formation of aluminium foil

This study investigated the adsorption of hydrogen bubbles and tunnel formation on aluminium foil during direct current (DC) electrochemical etching in an electrolyte with and without silicone oil additive. The results indicated that the etched tunnels obtained in the electrolyte containing silicone oil were more uniformly distributed with a more consistent size and length. This was attributed to the additive ability to facilitate the desorption of large bubbles on the aluminium surface, resulting in uniform corroded regions. Moreover, the generated narrow tunnels can accelerate the hydrogen evolution inside the tunnels, resulting in increasing the length of the etched tunnels.