Fabrication of porosity-graded biocompatible structures by 3D printing of Co-Cr-Mo alloy

Manufacturing of complex-shaped bimetals utilizing 2C-PIM (two-color powder injection molding) and 3DP (three-dimensional printing) processes, which basically involve sintering of a powder/binder mixture, has been attracted a great interest. This article addresses sintering of biocompatible Co-Cr-Mo alloy for manufacturing stepwise porosity-graded composite structures. Such composite structures provide strength at the core and a porous layer for the tissue growth. To evaluate the process, two grades of gas atomized Co-Cr-Mo powder with an average particle size of 19 and 63 micron were used. Isothermal and nonisothermal sintering behavior of the loose powders under hydrogen and argon atmospheres was studied. Microstructural characteristics of the sintered specimens were evaluated. It was found that an intermediate sintering temperature of 1280 deg C in argon can be used for manufacturing of the porosity-graded composite layers consisting of a relatively dense core (5 % porosity) and a porous surface layer (33 % porosity). A hip-joint with a core/shell structure was produced as a case study. Entnommen aus <a_href="http://www.fiz-technik.de/db/b_tema.htm" target="_blank">TEMA</a>