Titanium
Formula: Ti — Titanium
Appearance: Silvery-grey lustrous metal
Hazard: Very low hazard (solid) · Powder flammable
Properties
Density 4.51 g/cm³ — roughly half that of steel, yet comparable in strength. Melting point 1668°C. Exceptional corrosion resistance due to an instantly self-repairing TiO₂ oxide layer. Biocompatible — used in surgical implants. The oxide layer can be grown to a precise controlled thickness by anodizing; different thicknesses produce different interference colors (the same physics as soap bubbles) without any dyes or pigments. Available as wire, sheet, or jewelry blanks.
Historical Context
Titanium was discovered in 1791 by William Gregor and named after the Titans of Greek mythology. It remained a laboratory curiosity until the Kroll process (1940) made large-scale production feasible. It became indispensable in aerospace (SR-71 Blackbird, ~93% Ti) and medicine (hip replacements, dental implants). The anodizing color process has been used by artists and jewelers since the 1970s.
Experiments
Anodizing Colors: Connect titanium to the positive terminal of a variable DC supply in sodium carbonate solution. Each voltage grows a precise TiO₂ layer thickness: ~20 V → deep blue, ~35 V → blue-green, ~55 V → pink, ~65 V → turquoise. No dyes — pure interference color. See the full voltage–color table in the experiment guide.
Gradient Anodizing: Step the voltage down while progressively submerging the piece to create a multi-color gradient on a single piece.
Experiments using this chemical:
- Titanium Anodizing - Dial in precise colors with voltage
Safety
Solid titanium sheet and wire are non-toxic and safe to handle. Titanium powder or fine swarf can be flammable — avoid creating dust. The anodizing process uses sodium carbonate solution (mild irritant) and low-voltage DC; normal safety precautions apply above 50 V.