ForMatter/Finishes/anodize/Titanium / niobium color anodize
finish_anodize_titanium_color

Titanium / niobium color anodize

anodize · iridescent · interference anodize, voltage-color anodize, niobium ano

Run voltage through titanium or niobium in an electrolyte and the surface grows a clear oxide whose thickness shifts the visible color — purple, blue, gold, magenta — without dye. Voltage picks the color, not chemistry. Niobium ano-jewelry, color-shifted titanium watches, body-mod implants.

Anodic oxide on Ti / Nb / Ta in a non-aggressive electrolyte (TSP, dilute phosphoric, or borate buffer). Color comes from thin-film interference: layer thickness ~30–250 nm depending on applied voltage (10–120 V typical). Each ~7 V step shifts color. Reverse-polarity strips and re-grows. No dye involved; surface is hard, biocompatible, drift-free. Niobium yields the broadest color range; titanium is more limited but standard for medical / aerospace markings.

character — iridescent, shifts with viewing angle, smooth, biocompatible.

Finish properties

  • leveliridescent
  • subcategoryinterference oxide on refractory metals
  • applies tometal
Produced by processesAnodizing

Second life

reversibilitymoderate — the oxide layer can be stripped chemically (NaOH bath) and re-anodized. Color is permanent unless stripped; reversal requires controlled chemistry.
blocks substrate recyclingno
renewabilityshop-renewable — strip and re-anodize at any anodizing-shop with the matching color bath. Field-renewability is zero (you cannot anodize on a job site).

Aluminum Anodizers Council technical bulletins; ASTM B580 anodic-coating standard.

Citations