Effect of Zinc Oxide Concentrations on Anodic Coated AZ91D Mg Alloy for Surface Modification Applications

Abstract

The AZ91D Magnesium (Mg) Alloy is broadly known as an attractive material with many applications ranging from military goods and aerospace to automobile applications due to its excellent properties in lightweight, machinability, and castability. Unfortunately, Mg Alloys are also prone to corrosion resulting in degradation of the components, which can lead to severe component failure and injuries. Thus, corrosion prevention is required for the AZ91D Mg alloy to increase its performance in the environment. This paper uses the anodising method to study the influence of Zinc Nitrate’s electrolyte concentrations on anodic coated AZ91D Mg Alloys. This method formed a thin film layer on the AZ91D Mg Alloy’s samples known as an anodic film, which can potentially reduce the corrosion activity on the surface of the substrate. To investigate the corrosion activity of the anodised samples, the corrosion rate value was calculated by immersion of coated samples in a salt solution. The coated and corroded surfaces' morphology, structure, and thickness are observed using a Scanning Electron Microscope (SEM). At the same time, the element content of the material will be determined using X-ray diffraction (XRD). Thus, the resulting influence of Zinc Nitrate electrolyte concentration by anodising method shows which concentration value successfully formed the best Zinc Oxide (ZnO) coating layer on AZ91D Mg Alloy samples. Furthermore, an anodisation method using suitable concentrations of Zinc Nitrate electrolyte can be further developed to form an appropriate surface treatment for automotive applications in resisting corrosion in its environment.