The Effect of Graphene Nanoplatelets Content on the Hardness of Mg6%Zn0.2%Mn Composites

The effect of graphene nanoplatelets (GNPs) content on the hardness of magnesium-based composites was studied. A magnesium-based composite, Mg6%Zn0.2%Mn with graphene nanoplatelets (GNPs), was fabricated via powder metallurgy process at room temperature and compressive pressures of 50kN for 20 minutes, which was then sintered at 500°C for 2 hours. It produced significant grain refinement microstructure. The change in microstructure was examined by 3D microscope analysis, and the hardness value was evaluated using the Vickers microhardness apparatus. This study demonstrated the importance of GNPs reinforcement with zinc and manganese for microhardness analysis in the sintered Mg-based GNPs composites. It also portrayed their influence on grain refinement of the microstructure. The hardness results agreed with the microstructure results, proving that the presence of GNPs increases the hardness of the Mg-based composites

Characterisation of Polymesoda bengalensis Shell Powder

Seafood shell is abundant and has no eminent use and thus, commonly regarded as waste.Reusing and converting it into a useful material can decrease the amount of waste.Therefore, a study of the crystalline structure should be performed before identifying the potential use of the material. Theaim of this study istoidentifythe element and polymorph of Polymesoda bengalensis shell. The characterisations involved the usage of X-ray powder diffraction (XRD), scanning electron microscope (SEM)andenergy-dispersive X-ray spectroscopy (EDX). The XRD study revealed that theshellpowder mostly consisted of aragonite. The analysis from SEM also revealed that the aragonite was in the form of rod-like crystal. The morphology of sectional, inner and outer surfaces of the shell was s foundthat the aragonite was arranged in the form of a cross-lamellar structure of various sizes. The elemental content of the shell showed that CaCO3in this shell contained large amounts of calcium and carbon