Experimental investigations of nano-Yttria (Y2O3) for electrochemical properties on Aluminum-based alloy

Abstract

Sometimes aluminum composites have shown the properties better than their base alloys, therefore in this experimental research investigations three weight percent of nano yttria (Y₂O₃₎ are added to aluminum alloy with composition of Al-Si-Cu-Mg to study the corrosion behavior in simulated seawater. The characterization of the fabricated three composites is carried out by X-ray diffraction, scanning electron microscopy supported by energy dispersive spectroscopy and atomic force microscopy for three nano Y₂O₃% of 0.1, 0.3 and 0.5 weight percent. These three low percent are not detected in XRD, while the α-Al and Si with suggested phases Mg₂Si and Al₂Cu are appeared at their 2θ values. The inspection by FESEM/EDS gave indication to the presence of nano yttria particles within the alloy structure that lead to the clustering and rupturing the tree-like structure of the dendrite, this observation is supported by the increasing in W and O content by EDS analysis with increasing the added percent in fabricated composites. AFM analysis reflects the roughness of the composite’s surface that related to appear cathodic and anodic sites, where the presence of the highest percent of nano yttria lead to increasing the cathodic area on the surface due to clustering the ceramic particles within metallic matrix. Electrochemical properties for fabricated composites compared with base alloy gave indication that the lowest addition is the best for corrosion resistance, where the corrosion current density is decreased by 1.5-6% for 0.1wt.% of nano yttria and all composites are shifted the corrosion potential to the cathodic direction confirming the increasing of the cathodic area as well as the variation in the Tafel slopes that give indication for occurring different reactions on the surface.