Powder injection moulding of porous titanium from titanium hydride powder and space holders

Titanium hydride is a cost-effective alternative to produce PIM titanium grade 4 parts. Biocompatibility, bone-like mechanical properties, and good bone-to-implant anchorage are current requirements for permanent implants. Porous titanium can satisfy these requirements provided that high enough porosity and big enough pores allowing bone ingrowth can be obtained with controlled processes. In this work, porous parts are processed from titanium hydride based feedstocks containing space holders. Two formulations have been developed: feedstock with polyethylenglycol-based binder and NaCl space holders, and feedstock with paraffin-based binder and PMMA space holders. Depending on sintering conditions, open porosity between 30% and 60% is obtained, with pore sizes in the range 50-500μm. The microstructure, porosity and mechanical properties of porous titanium sintered at different temperatures are characterized by optical microscopy, SEM, image analysis, compression and bending tests.