Gelcasting of porous titanium implants

Abstract

Porous titanium implants with large size and complex shape were successfully fabricated by a novel near net forming process, gelcasting, and the effects of processing parameters on the viscosity of the Ti slurry based on acrylamide system, dry green strength, porosity and mechanical properties of sintered body were investigated. The viscosity of Ti slurry with 34 vol.-%Ti and 20 wt-% monomer based on the premix dispersed by 0˙4 wt-%NH₄OH is <1 Pa s when the shear rate is >20 s^-1. A green body with the strength of 30 MPa can be obtained from the 34 vol.-%Ti slurry with the ratio of monomer to cross-linker from 3 to 120, and when sintered at 1373 K for 1˙5 h, the total porosity and open porosity of porous titanium were 46˙5 and 40˙5% respectively, and its mechanical properties are compressive strength ∼192 MPa, Young's modulus ∼8˙5 GPa, similar to those of human cortical bone and appropriate for implanting purpose.

Keywords:

• GELCASTING
• POROUS TITANIUM
• COMPLEX SHAPE
• IMPLANT