The effect of HAP addition on the physical and mechanical properties of co-cr-mo/HAP composites for biomedical apllications

Abstract

This paper reports on the effect of HAP addition on the physical and mechanical properties of Co-Cr-Mo/HAP composites fabricates by powder metallurgy. Co-Cr-Mo is used in orthopedic because of its excellent biocompatibility when implanted to human or animal body. Hydroxyapatite (HAP) powders have been used as fillers because of its similarity to minerals constituents of bones and teeth makes it as the one of the most effective biocompatible materials. HAP powders with the chemical formula Ca10(PO4)6 (OH)2 have been added to Co-Cr-Mo alloys in composition of 0, 3, 6 and 9 wt. %. These mixture were then milled, cold compacted at 550 MPa before sintered at 1100oC in a tube furnace. The density, porosity and microhardness were measured. The composites of Co-Cr-Mo/0HAP showed better physical and mechanical properties than others composites. After sintering, Co-Cr-Mo/3HAP show higher bulk density (6.6672) and the Co-Cr-Mo/0HAP composites show the highest true density (8.4306) compared with others sample. The percent of porosity increased (22.20%, 15.51%, 28.99%, 32.65%) as the HAP addition is increased (0 wt. %, 3 wt. %, 6 wt. %, 9 wt. %) respectively. As the HAP addition is increased from 0 wt. % to 9 wt. % the value microhardness of the composites is decrease from 128.5 HV to 69.5 HV. Microstructural analysis for line scan showed that, as the more addition of HAP is increased, more pores can be seen. In the elemental analysis, the EDS results shows that as the addition of HAP is increased, the present of calcium (Ca) and phosphorus (P) elements is increased.