When to pick CoCrMo
CoCrMo is biocompatible, exceptionally wear-resistant, and retains strength above 600 °C. It is the default for dental crowns and bridges, orthopedic knee and hip components, and high-temperature aerospace parts where Ni superalloys are overkill.
Defects and post-processing
L-PBF CoCr is prone to cracking if the build plate is cold — pre-heat is essential. The solution treatment dissolves σ-phase and gives the listed properties; without it, ductility is low.
For implants, hot isostatic press and electropolish are standard.
Suggested parameters
Starting recipe at 30 µm layer.
- Layer thickness: 30 µm
- Laser power: 200 W
- Scan speed: 900 mm/s
- Hatch spacing: 90 µm
- Pre-heat: 200 °C plate
- Atmosphere: argon, O₂ < 100 ppm
Frequently asked questions
Is L-PBF CoCr suitable for permanent implants?
Yes — F75-compliant L-PBF CoCr is approved for orthopedic and dental implants by multiple regulatory bodies. Final clearance is always per-device.
Why is pre-heat so critical?
CoCr has a high coefficient of thermal expansion and low thermal conductivity. A cold plate concentrates thermal gradients and cracks the part.
Sources
- ASTM F75 / F1537 — Wrought and Cast CoCrMo
- ASTM F3213 — AM CoCrMo for medical use
- EOS CobaltChrome SP2 datasheet