Effect of Zn concentration on microstructure and corrosion resistance of Mg-Zn alloys microalloyed with Ca and Ce

Abstract

Purpose

The influence of Zn concentration on microstructure and corrosion performance of the Mg–xZn alloys microalloyed with Ca and Ce was investigated through optic microscopy, scanning electron microscopy, hydrogen evolution, dynamic polarization and electrochemical impedance spectroscopy experiments.

Design/methodology/approach

In this paper, Mg–xZn alloys (x = 0.5∼2.0 Wt.%) microalloyed with Ca and Ce (0.2 Wt.% each) were prepared.

Findings

As the increase of Zn concentration, the number of second phase particles (Mg-Zn-Ca, Mg-Zn-Ce and Mg-Ce phases) increased, and when the Zn concentration increased to 2.0 Wt.%, the new second phase Mg-Zn phase was precipitated.

Originality/value

The influence of Zn concentration on corrosion mechanism of Mg-xZn alloys microalloyed with Ca and Ce was revealed. Increasing of the Zn concentration resulted in the intensification of galvanic corrosion. When Zn concentration was 0.5 Wt.%, the alloy showed the lowest corrosion rate (0.61 mm y-1), which was about 1/2 of that of Mg-2.0Zn-0.2Ca-0.2Ce alloy.

Citation

Zhang, C., Peng, C., Huang, J., Zhao, Y., Huang, G., Wu, L., Wang, G. and Zhang, H. (2021), "Effect of Zn concentration on microstructure and corrosion resistance of Mg-Zn alloys microalloyed with Ca and Ce", Anti-Corrosion Methods and Materials, Vol. 68 No. 2, pp. 130-136. https://doi.org/10.1108/ACMM-11-2020-2407