Surface and corrosion properties of corn cob and egg shell particles reinforced AA3104-H19 composite via stir casting process

Aluminium alloys have been the most commonly used materials in the automotive and marine industries. However, depreciation in strength due to contact with environmental contaminants occurs over time. Hence, this study examined the effect of corn cob (CC) and egg shell (ES) particles on the corrosion, hardness and microstructure properties of AA3104-H19 composite. The corrosion experiment was conducted in 3.65 wt% NaCl solution. The microstructure of the material was examined with a scanning electron microscope (SEM) and X-ray diffractometer (XRD). The hardness was measured using a simple Brinell hardness tester loading. The control sample (AA3104-H19 alloy) exhibited the highest corrosion rate (CR) and corrosion current density (jcorr) of 0.0914 mm/year and 7.867 μA/cm2, respectively, Al90%-CC10%-ES0% sample exhibited the lowest CR and jcorr of 0.0135 mm/year and 1.16 μA/cm2, respectively. More so, the control sample exhibited a Brinell hardness of 96.3 kgf/mm2, while the Al90%-CC0%-ES10% sample exhibited an improved Brinell hardness of 99.6 kgf/mm2. The low corrosion rate of Al90%-CC10%-ES0% and high Brinell hardness Al90%-CC0%-ES10% of samples indicated that the samples exhibited superior corrosion resistance and enhanced resistance to indentation, respectively, relative to the other test samples. The SEM images revealed that the reinforced samples exhibited more uniform morphology than the control sample. The presence of AlSiO2 as indicated by the XRD results could have enhanced the corrosion rate of the material. The ESD revealed elements such as Ca, Mg, Si, Al and C, which are beneficial to the surface and corrosion properties of the material.