Corrosion Behavior and In-Vitro Bioactivity of Porous Mg/Al 2 O 3 and Mg/Si 3 N 4 Metal Matrix Composites Fabricated Using Microwave Sintering Process Publisher



Ghasali E¹ ; Bordbarkhiabani A² ; Alizadeh M¹ ; Mozafari M² ; Niazmand M¹ ; Kazemzadeh H³ ; Ebadzadeh T¹ Show Affiliations
Source: Materials Chemistry and Physics Published:2019

Abstract

In the present work the corrosion behavior and in-vitro bioactivity of two kinds of porous Mg-metal matrix nano-composites separately reinforced with Al 2 O 3 whiskers and Si 3 N 4 particles were reported. 10 wt% of reinforcement was mixed with magnesium using high-energy ball milling and ethanol media for 10 min. After that, 10 ml ethylene glycol was added to milled mixture at the final stage of drying on a heater/stirrer at 70 °C. After stirring for 12 h, the powder mixtures were uniaxially pressed at 300 MPa to produce bar-shaped green specimens. The microwave sintering was performed at 650 °C without soaking time in a graphite bed. Porosity of about 50% was measured for both sintered composites using Archimedes principle. The XRD investigations revealed Mg 2 Al 3 and MgO phases as the result of reaction between Mg and Al 2 O 3 . Moreover, the reaction products in Mg- Si 3 N 4 composite were Mg 2 Si, Mg 3 N 2 and Si. The corrosion tests showed that the polarization resistance of both prepared composites is higher than that of pure Mg. Mg-Al 2 O 3 composite also showed lower corrosion current density compared to Mg- Si 3 N 4 composite (1.42E −4 and 1.36E −3 A cm −2 , respectively). In-vitro bioactivity analysis of composites showed high level of needle-shaped CA-P inside porosities of Mg-Si 3 N 4 composite; while in the case of Mg-Al 2 O 3 composite a lower amount and smaller needle-shaped particles were found. © 2019 Elsevier B.V.