Archachatina marginata bio-shells as reinforcement material in metal matrix composites

Abstract

Snail shells (SnS), which represent the discarded bio-shell waste of snails’ remnants from restaurants and eateries constitute a serious degree of environmental threat with little or economic value. The effective utilisation of this waste into a green metal matrix composite as a low cost reinforcement material applicable in the automotive industry in lieu of its present hazardous impact had stimulated the research interest. Hence, this paper studies the potential utilisation of SnS as a low cost reinforcement material in the metal matrix composites (MMCs) by means of a characterisation technique. The mineralogical composition and physical properties of the snail shell powder was carried out using the density determination, thermogravimetric analysis (TGA), refractoriness, energy dispersive X-ray (SEM/EDX), X-ray fluorescent (XRF) and the X-ray diffraction (XRD) analysis at 0, 800, 850 and 900 oC calcined temperatures for 3hrs. The results obtained show that the snail shell powder possesses chemical hard phase oxides (CaO, Fe2O3, Al2O3, Cr2O3, SiO2, MnO and NiO) at all calcined temperature values. The maximum amount of these phases was formed at a 900 oC calcined temperature. The XRD analysis also confirmed the presence of calcite (Ca6C6O8), lime (Ca4O4) and portlandite (CaO2H2) as the thermally stable major hard phases of the SnS calcined at 900 oC. The density and refractoriness temperature of the snail shell powder as obtained in this study are 1.63 g/cm³ and 1400 oC. The TGA result shows that the SnS attained its thermal stability at 840oC. The above results imply that SnS with (9.4-25.9) % lesser density when compared with agro or industrial wastes reinforcement material (flyash, coconut shell ash, maize husk, bagasse) in the metal matrix composite looks promising as a reinforcing material in the production of light weight metal matrix composites at low costs. Also, the high refractoriness temperature of the snail shell particle suggested it as a suitable candidate reinforcement material in the production of thermal resistance MMCs applicable in automotive components such as pistons and connecting rods.