Assessing the effect of different biodiesels on corrosion of nickel alloy

Abstract

This investigation explores the corrosion behaviour of Ni alloy (UNS718), which is a potential material for storing biodiesel and making engine components. The study also examines the connection between Ni alloy corrosion and biodiesel degradation. Immersion tests were conducted using in-house biodiesels to evaluate the corrosion rates of Used Cooking Oil (UCOB), Karanja oil (KOB), and Jatropha oil (JOB) biodiesels on Ni alloy (UNS718). The results highlighted the role of corrosion product morphology and the formation of corrosion-driven pitting, cracks, etc., on Ni alloy when exposed to different biodiesels such as KOB, JOB, and UCOB. The study utilized gravimetric techniques to measure the corrosion rate and advanced analytical tools such as FESEM, EDS, XPS, NMR and XRF. It revealed decreased corrosion rates of Ni alloys with prolonged biodiesel immersion. For example, after 2160 h, Jatropha biodiesel exhibited a corrosion rate of 0.000699 mm/year, while the corrosion rates of Ni alloy exposed to UCOB and KOB were 0.001398 mm/year and 0.001048 mm/year, respectively. The study also suggests a detailed mechanism of Ni alloy corrosion when exposed to different biodiesels such as Karanja, Jatropha, and Used Cooking Oil.