The effect of biodiesel fuel made from rapeseed oil and methanol on the corrosion properties of copper, mild carbon steel, aluminum, and stainless steel was studied and compared with those of commercial diesel fuel. The results show that the metals mentioned above corroded with variable degrees as they were immersed in the biodiesel fuel at 43 degrees C for 60 days. Their corrosion rates were 0.02334, 0.01819, 0.00324, and 0.00087 mm/year, respectively. However, the corrosion rates of the metals immersed in commercial diesel fuel were relatively lower under the same corrosion conditions. The effects of biodiesel on the corrosion of copper and mild carbon steel were more significant than on aluminum and stainless steel. The corrosion process of metal surfaces in the biodiesel was mainly attributed to the chemical corrosion according to the experimental results with the help of SEM/EDS. MS, and XPS. (C) 2011 Elsevier Ltd. All rights reserved.