Comparison on the corrosion rates of copper, zinc and brass in Pongamia and Jatropha biodiesels

Abstract

Corrosion is one of the most important topics very relevant to the biodiesel compatibility issue. The corrosive effects of biodiesel are mainly caused by the presence of water and free fatty acids. In the present investigation, the compatibility of biodiesels from Pongamia, Jatropha and their different blends (5%, 10% and 20%) with diesel on copper, zinc and brass has been studied by mass loss method for a period of 100 h. Though the studied metals in pongamia, jatropha and diesel blends behave in different magnitude, the least corrosion rate is observe in commercial diesel when compare to biodiesels in all the metals. The effect of temperature on the corrosivity of biodiesels and their blends with diesel has been investigated by linear polarization resistance method. The changes in surface morphology and corrosion products on the biodiesels expose metal surfaces examined by optical microscope and X-ray diffraction. Copper and brass coupons in JBD show only base metal peaks and intense carbonate peak in zinc which prove the least corrosivity of JBD in studied metals.