Fabrication, microstructure and corrosion study of porous Mg-Ca-Zn using CaCO3 pre-treatment with sodium trisilicate

Abstract

Magnesium-based alloys have the good potential as a biodegradable implant that can be degraded in biological tissue. In this research, the fabrication of porous implant materials based on Mg-Ca-Zn alloy develop by powder metallurgy. CaCO₃ as a foaming agent which previously coated by using sodium trisilicate has been used to obtain open celullar pores. The alloy compositions used in this research are Mg-Ca-3Zn-5CaCO₃ and Mg-Ca-3Zn-10CaCO₃. Sintering process is carried out at temperature of 600, 650 and 700 °C with holding time of 5h. The alloy is characterized by using XRD (microstructure analysis), SEM (surface and pore analysis) and corrosion test of alloys (electrochemical analysis using tafel graph). The microstructures of the alloy show MgO and Mg₂Ca phase SEM results show the pores in the alloy with the size approximately arround 194.843-266,938μm. The corrosion rate in alloys is obtained in the range of 0.4-3.2 mmpy. The morphology of the alloy surface after corrosion process shows the volcano type. The corrosion process occurs localized where the electrochemical reaction occurs, so as to form a distinctive structure with the shape of the circle and the hole in the middle.