Increased Shape Stability and Porosity of Highly Porous Injection‐Molded Titanium Parts

Highly porous titanium parts in three different shapes (conical, cylindrical, and semi‐cylindrical) were produced using metal injection molding (MIM) and the space holder technique. Potassium chloride (KCl) powder was used as a temporary space holder material. The frequently used extraction of the KCl space holder by dissolution in warm water was replaced with sublimation from the solid state during vacuum sintering. This improvement enabled highly porous titanium parts to be manufactured by MIM without the frequently observed sample collapse or extensive shape distortion. Final porosities of 55–60% were achieved, which is close to the recommended value for porous spinal titanium implants, making improved method attractive for implant manufacturing applications. An additional advantage of removing the space holder by sublimation is that the time‐consuming salt leaching step can be omitted. A systematic study of sample configuration, porosity change, microstructure, and impurity uptake was conducted and the sintering cycle was optimized.