Abstract

Jatropha biodiesel fuel as a renewable energy source has gained prominence over time. The utilization of jatropha biodiesel fuel and its effects on engine components in automobiles needs to be interrogated to provide sufficient data on metal degradation and solution contamination. Electrochemical (EIS, OCP and PDP) and morphological (SEM) studies on the behaviour of mild steel immersed in jatropha biodiesel fuel is investigated in this research. The study elucidated on the jatropha biodiesel fuel-metal surface interactions at room temperature (25℃) and different time intervals (0, 7, 28, 42 and 56 days). Electrochemical measurements established that mechanism of corrosion of the mild steel surface was physical and this corroborated with morphological investigations which showed gradual but consistent surface degradation over time due to material dissolution in the biodiesel fuel (corrosion rate (CR) of 103 mpy, corrosion potential (𝐸 𝑐𝑜𝑟𝑟 ) of -586 mV/SCE, corrosion current (𝑖 𝑐𝑜𝑟𝑟 ) of 16.23 μA/cm 2 , and standard deviation of 0.44). Thus, the degradation of mild steel in jatropha biodiesel fuel showed high level of surface instability resulting in significant corrosion over time and therefore provided a means of ascertaining the compatibility and effectiveness of the mild steel with regards to the specific biodiesel fuel in automobile engines. Essentially, the corrosion attack arose mainly due to the presence of C18 fatty acid groups in the jatropha biodiesel fuel. To mitigate the attack on the mild steel by the fatty acid molecules, corrosion inhibitors that are environmentally friendly, non-reactive and non-toxic could be incorporated into the fuel.