CoCrMo Alloys
CoCrMo alloys are widely used for medical prosthetic implant devices. The alloys are especially used where high stiffness or a highly polished and extremely wear-resistant material is required. CoCrMo alloys are the materials of choice for applications such as knee implants, metal-to-metal hip joints and dental prosthetics.
CoCrMo Alloys Basic Introduction
CoCrMo alloys are widely used for medical prosthetic implant devices. The alloys are especially used where high stiffness or a highly polished and extremely wear-resistant material is required. CoCrMo alloys are the materials of choice for applications such as knee implants, metal-to-metal hip joints and dental prosthetics.
CoCrMo Alloys Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.350 max |
| Chromium (Cr) | 27.000-30.000 |
| Molybdenum (Mo) | 5.000-7.000 |
| Nickel (Ni) | 0.500 max |
| Iron (Fe) | 0.750 max |
| Silicon (Si) | 1.000 max |
| Manganese (Mn) | 1.000 max |
| Tungsten (W) | 0.200 max |
| Phosphorus (P) | 0.020 max |
| Sulphur (S) | 0.010 max |
| Nitrogen (N) | 0.250 max |
| Aluminium (Al) | 0.100 max |
| Boron (B) | 0.100 max |
| Titanium (Ti) | 0.100 max |
| Cobalt (Co) | Balance |
Summary
ASTM F75 is a non-magnetic CoCrMo alloy exhibiting high strength, corrosion resistance, and excellent wear resistance. It is widely used for orthopaedic and dental implants. Highly polished components include femoral stems for replacement hips and knee condyles. Other cobalt medical implants include acetabular cups and tibial trays. In all cases, but especially in hip components, material quality is imperative as parts are heavily loaded and subject to fatigue.
