Improvement of the mechanical properties and corrosion resistance of biodegradable (beta-Ca-3(PO4)(2)/Mg-Zn composites prepared by powder metallurgy: the adding beta-Ca-3(PO4)(2), hot extrusion and aging treatment

摘要

In this study, 10%beta-Ca-3(PO4)(2)/Mg-6%Zn (wt.%) composites with Mg-6%Zn alloy as control were prepared by powder metallurgy. After hot extrusion, the as -extruded composites were aged for 72 h at 150 degrees C. The effects of the adding beta-Ca-3(PO4)(2), hot extrusion and aging treatment on their microstructure, mechanical properties and corrosion resistance were investigated. The XRD results identified alpha-Mg, MgZn phase and beta-Ca-3(PO4)(2) phase in these composites. After hot extrusion, grains were significantly refined, and the larger-sized beta-Ca-3(PO4)(2) particles and coarse MgZn phases were broken into linear-distributed beta-Ca-3(PO4)(2) and MgZn phases along the extrusion direction. After aging treatment, the elements of Zn, Ca, P and 0 presented a more homogeneous distribution. The compressive strengths of the beta-Ca-3(PO4)(2)/Mg-Zn composites were approximately double those of natural bone, and their densities and elastic moduli matched those of natural bone. The immersion tests and electrochemical tests revealed that the adding beta-Ca-3(PO4)(2), hot extrusion and aging treatment could promote the formation of protective corrosion product layer on the sample surface in Ringer's solution, which improved corrosion resistance of the beta-Ca-3(PO4)(2)/Mg-Zn composites. The XRD results indicated that the corrosion product layer contained Mg(OH)(2),beta-Ca-3(PO4)(2) and hydroxyapatite (HA). The cytotoxicity assessments showed the as -extruded beta-Ca-3(PO4)(2)/Mg-Zn composite aged for 72 h was harmless to L-929 cells. These results suggested that the beta-Ca-3(PO4)(2)/Mg-Zn composites prepared by powder metallurgy were promising to be used for bone tissue engineering. (C) 2017 Elsevier B.V. All rights reserved.