Titanium anodizing — the process of growing a controlled oxide layer that produces interference colors — works well on MIM titanium Ti6Al4V parts, with some important process considerations.
Color palette achievable on MIM Ti6Al4V:| Voltage (V) | Color | Oxide Thickness | Typical Applications |
|---|---|---|---|
| 10-20 | Gold / Straw | 20-30 nm | Medical instrument identification, decorative |
| 25-40 | Blue / Purple | 40-80 nm | Medical implant distinction, branding |
| 45-60 | Green / Teal | 80-120 nm | Consumer goods, wearable components |
| 65-80 | Red / Pink | 120-160 nm | Cosmetic accents, medical coding |
| 85-100 | Grey / Dark | 160-200 nm | Industrial, functional (thicker oxide = more wear resistance) |
| Factor | Consideration | Recommendation |
|---|---|---|
| Surface finish | As-sintered (Ra 2.0-3.2 µm) produces duller colors | Polish to Ra < 0.8 µm for vibrant colors |
| Density | Porosity can trap acid electrolyte | Ensure > 96% density to prevent acid entrapment |
| Pre-cleaning | MIM parts must be free of mold release, oils | Ultrasonic clean + alkaline degrease before anodizing |
| Masking | Complex internal geometry is hard to mask | Design anodizing fixtures before mold is built |
| Color consistency | PSD variation can cause slight color shift between lots | Specify acceptable color range using Lab* coordinates, not visual match |
Yes — MIM Ti6Al4V parts can be anodized to produce the same range of colors as wrought titanium (gold, blue, purple, green, red, grey). The key requirement is >96% sintering density to prevent acid electrolyte from being trapped in surface pores. For the most vibrant and consistent colors, specify a polished surface finish (Ra < 0.8 µm) before anodizing.
Color anodizing on MIM titanium is commonly used for medical instruments (color-coded by size), consumer electronics (cosmetic accents), and dental components (aesthetic matching). The anodized layer is 20-200 nm thick and does not affect dimensional tolerances.