The various specifications used in the anodising process, three of which are types of aluminium anodisation (chromic acid anodising, sulfric acid anodising and sulfric acid hardcoat anodising), but also non-aluminium based types such as phosphoric acid anodising, organic acid anodising, plasma electrolytic oxidation, and borate and tartrate baths.
Data Source: Unified Global Standards (ISCED, ISCO, O*NET, ESCO)