PI-WIKI-PHYS-08 · Materials Science · reviewed 2026-10-31
Anodized Titanium Oxide Colour: Physics & Market Guide
Critical numbers
Voltage RangeUp to about 100-120 V DC
Oxide Thickness RangeA few nm (natural film) to about 150-300 nm
Growth RateAbout 1.4-2.8 nm per volt, by electrolyte [1]
Oxide CompositionTiO₂ (titanium dioxide)
TiO₂ Refractive IndexHigh (well above glass); varies with structure
Colour vs VoltageAlloy- and setup-specific; build a reference chart [4]
Process (body jewelry)Colour anodizing, thin interference film
Electrolyte (typical)Dilute TSP or ammonium sulfate, room temperature
Surface Hardness (TiO₂)~5–6 Mohs
Substrate StandardASTM F136 Ti-6Al-4V ELI (implant grade) [5]
UV StabilityExcellent, interference colour is not UV-degradable
Do not
- Confusing anodization with plating when advising clients
- Accepting plated-to-look-like-titanium jewelry from discount suppliers
- Ultrasonically cleaning anodized jewelry in alkaline solution
- Assuming all "titanium" is implant grade
- Trying to reach a lower-voltage colour by re-anodizing
- Using anodized jewelry in fresh piercings as a colour preference without…
Applicable standards
- European Union — ISO 5832-3 (Ti-6Al-4V) and ISO 5832-2 (unalloyed titanium)
- United States — ASTM F136-13(2021)
- ASEAN & Asia-Pacific — Thailand