Overview of the interactions between automotive materials and biodiesel obtained from different feedstocks

At present, biodiesel is receiving an alarming attention as a potential alternative to conventional petroleum diesel. However, unsaturated molecules, free fatty acids, oxygenated moieties of biodiesel are highly reactive with metal surfaces and thus create major concern with the sustainability of engine parts. To assess the degradation behavior of engine materials in different biodiesels, most of the published studies are carried out either in the laboratory or by field trial tests with a limited number of variables. The scattered studies hardly provide a clear concept on the comparative degradation of different materials in biodiesel, the related causes and mechanisms. This study aims to investigate the overall interactions between automotive materials and biodiesels obtained from different sources including palm, rapeseed, jatropha, and soybean. >100 scientific research papers are reviewed, and data on material degradation are analyzed and discussed. The investigated automotive materials include ferrous, non-ferrous and elastomer materials. This comprehensive review presents the aggressive constituents of biodiesel, their sources, and key factors that influence metal and elastomer degradation. The impact of feedstock and production technologies on the corrosiveness of biodiesel is also discussed. Finally, this article provides a deeper understanding on possible degradation mechanism of ferrous, non-ferrous, and elastomer materials. •Sustainability of biodiesel for automotive applications•Impact of feedstocks and processing technology on the corrosiveness of biodiesel•Corrosion mechanisms of different ferrous and non-feorus metals upon exposure to biodiesel•Degradation mechanism of elastomers upon exposure to biodiesel.