Study of electrochemical behaviour of AZ91 Mg-based composites

Abstract

In this research study, electrochemical behaviour of AZ91/12Al2O3 and AZ91/12Al2O3/3TiC composites are investigated using different methods such as linear polarization resistance, electrochemical spectroscopy, noise measurements, and potential dynamic polarization curves. Both composites have been fabricated by using a two-step stir casting process. These composites include alumina (Al2O3) and TiC (titanium carbide) as reinforcing particles amalgamated with AZ91 Mg alloy. However, AZ91 Mg alloy depicts 9% of aluminium, 1% of zinc and rest is balance of pure magnesium, AZ91/12Al2O3 signifies AZ91 Mg alloy having 12 wt. % of alumina whereas AZ91/12Al2O3/3TiC indicates 3 wt. % of titanium carbide and 12 wt.% of Al2O3 in AZ91 Mg alloy. The conclusive result of these methods illustrate that AZ91/12Al2O3 composite exhibits high corrosion rate as compared to AZ91/3TiC/12Al2O3 composite due to high galvanizing effect (in between corrosive surface) of AZ91 Mg alloy and alumina particles. Lastly, the results of the electrochemical impedance of both composites illustrate the diffusion/adsorption type phenomenon.