Abstract
Nine types of metal including bonderized iron, iron, black scale, mild steel, copper, brass, aluminum, SUS 304 and SUS 316 were immersed in rubber seed oil (RSO) at 303, 318 and 328 K to investigate the corrosion behavior of the metals in this oil. Cooking palm oil (CPO) was used as a reference, which contains a lower concentration of free fatty acids (FFA) than RSO. The acid values (AV) of the RSO and CPO were 91.4 and 0.23 mg-KOH/g, respectively. The metals used in this study showed constant corrosion rates in RSO throughout the time period of the corrosion test (28 d). The following order for the corrosion rate was observed: mild steel > iron=bonderized iron = black scale > brass = copper > SUS304 = SUS316 = aluminum. SUS304, SUS316 and aluminum exhibited no substantial corrosion in RSO. The activation energy for the corrosion rate was calculated for iron, mild steel, copper and brass to be 61.4, 46.9, 29.0 and 23.2 kJ/mol, respectively. The corrosion rate of all the metals in CPO was substantially zero at 318 and 328 K.
