Investigations on the Microstructure and Degradation Behavior of Hollow Glass Microspheres/Mg Alloy Composites

Degradable materials with low density exhibit unique applications in the petroleum equipment field. Herein, hollow glass microspheres (HGM)-reinforced Mg alloy degradable composites are fabricated. The microstructure and degradation behavior of the composites are investigated using scanning electron microscopy, immersion tests, and electrochemical measurements. Then the influence mechanisms of the HGM on the degradation property of composites are further revealed. The results show that the addition of the HGM significantly reduces the density of the composites. Different degrees of chemical reaction between the Mg alloy melt and HGM wall happen during the fabrication of the composites, resulting in the formation of MgO and Mg2Si. From the corrosive morphologies of the composites, Mg2Si phase can serve as a microgalvanic cathode consequently inducing more galvanic corrosion. The interface between HGM and matrix alloy can serve as the initiation site for pitting corrosion and increase the exposed area of the matrix in the aggressive medium. The electrochemical measurements prove that the HGM can act a part in facilitating the exfoliation of degradation products. Consequently, the HGM greatly increases the degradation rate of the composites in the KCl solution. The current study provides a new insight for developing lightweight Mg-based composites with quickly degradable performance.

Automated summary

The addition of HGM significantly reduces the density of the composites. Different degrees of chemical reaction between the Mg alloy melt and HGM wall occur during the fabrication of the composites, resulting in the formation of MgO and Mg2Si. The interface between HGM and matrix alloy can serve as the initiation site for pitting corrosion and increase the exposed area of the matrix in the aggressive medium.