Influence of Al2O3 nanoparticles on the corrosion behavior of biomedical cocrmo alloy in Ringer's solution.

The current research aims to study the influence of α-A_l2O₃ nanoparticles on the corrosion resistance and behavior of biomedical Co29Cr6Mo alloy. Base alloy and nano-composites with additions of 1, 3 and 5 wt% of α-Al₂O₃ nanoparticles were made-up via powder metallurgy route at the best applied pressure of 1000MPa and sintering temperature of 1200°C for 2hrs. Measurements of bio-corrosion tests were accomplished for all prepared samples in pH7.4 Ringer's solution and at 37°C. It has been found that the addition of Al₂O₃ nanoparticles decreased the bulk density from 7.16 to 6.033 gm/cm3 and increased the porosity of the alloy by 13.34% when the addition was 5wt%. SEM-EDS and XRD analysis revealed that the phases forming in microstructure of CoCrMo alloy consisted mainly of both γ-Co and ε-Co beside Cr₂O₃ oxide. The resistance of CoCrMo base alloy to corrosion in Ringer's solution was upgraded when nano Al₂O₃ were added with (1, 3 and 5) wt% by decreasing the corrosion rate (47, 3.26 and 2) times respectively. Cyclic polarization tests revealed somewhat pitting corrosion occurrence when 1wt% Al₂O₃ nanoparticles were added to CoCrMo alloy. Furthermore microstructure remarks by optical, SEM and SEM-Mapping techniques discovered the absence of inter-particle and intergranular corrosion types within the CoCrMo particles when Al₂O₃ nanoparticles were added to CoCrMo alloy. [ABSTRACT FROM AUTHOR]