Some metals can be made even better through a simple process called anodisation. When you anodise metal, you increase the thickness of the oxide layer on the base metal, thus giving it a number of advantages such as: increased corrosion and wear resistance, increased lubricity by reducing friction, improved adhesion, and decreased galling of threaded components, among others. The most common anodised metal is aluminium, but other metals such as zinc, zirconium, magnesium, hafnium, tantalum, and titanium can also benefit from the process.
The anodisation process involves dipping the metal into a bath that contains an acid electrolyte and cathode. An electric current passes through the acid bath and the metal becomes the anode, which is where the process gets its name. The electric current prompts an oxide to form on the surface of the anode and from the acid, oxygen ions emanate.