Effect of calcium content on the microstructure, hardness and in-vitro corrosion behavior of biodegradable Mg-Ca binary alloy

Abstract

Effect of calcium addition on microstructure, hardness value and corrosion behavior of five different Mg-xCa binary alloys (x = 0.7, 1, 2, 3, 4 wt. (%)) was investigated. Notable refinement in microstructure of the alloy occurred with increasing calcium content. In addition, more uniform distribution of Mg 2 Ca phase was observed in α-Mg matrix resulted in an increase in hardness value. The in-vitro corrosion examination using Kokubo simulated body fluid showed that the addition of calcium shifted the fluid pH value to a higher level similar to those found in pure commercial Mg. The high pH value amplified the formation and growth of bone-like apatite. Higher percentage of Ca resulted in needle-shaped growth of the apatite. Electrochemical measurements in the same solution revealed that increasing Ca content led to higher corrosion rates due to the formation of more cathodic Mg 2 Ca precipitate in the microstructure. The results therefore suggested that Mg-0.7Ca with the minimum amount of Mg 2 Ca is a good candidate for bio-implant applications.

Effect of Warm Rolling on Microstructure and Mechanical Properties of Twin-roll Casted ZK60 Alloy Sheets

“…Mg and its alloys have been widely applied in the industrial area 1 . However, the strength of Mg alloys is relatively low at room temperature and the manufacturing cost is high.…”

Structure, mechanical property and corrosion behaviors of (HA + β-TCP)/Mg–5Sn composite with interpenetrating networks

“…Afterwards, this film gradually transformed to the hydrate state (Mg(OH) 2 ·nH 2 O) while being soaked in the solution. Preparation process of SEM sample caused dehydration which brought about shrinkage of the film and the formation of cracks [36]. From the above results, it is reasonable to deduce that shortly after the implantation of the compsosite in the bone, the bone tissue will grow towards the degradation of Mg-5Sn matrix alloy while the remaining HA + β-TCP networks still maintain their geometrical shape and carry the physiological load for the tissue ingrowth [18].…”

Enhanced Mechanical Properties and Corrosion Behavior of Biodegradable Mg-Zn/HA Composite

“…The occurrence of Mg corrosion increased the pH of the solution due to the reduction of H + as a result of the H 2 release. [36,37] The polarization curves for various sintered compacts are given in Figure 7. The electrochemical parameters, including corrosion potential (E corr ), corrosion current density (I corr ), and polarization resistance (R p ), obtained from the polarization curves by the Tafel extrapolation method and electrochemical impedance spectroscopy studies are listed in Table IV.…”