Tribocorrosion Behaviour of Biodiesel ^|^mdash; A Review

Abstract

Biodiesel serves as the best alternative candidate to diesel fuel for diesel engines as a result of its ability to function as substitute to meet with the rising energy demand. Biodiesel is considered more environmentally friendly than fossil fuel because it is made from renewable resources and has lower emissions. This paper focuses on the tribocorrosion behaviour of biodiesel followed by development of tribocorrosion model with the aim of understanding the combined effects of tribology and corrosion (synergism) for automotive tribo-component materials under biodiesel. A systematic review analysis was performed on tribology and corrosion test analysis for different biodiesel feedstock and factors affecting tribocorrosion system. Established theoretical model has been developed to evaluate the corrosive wear of materials with a well-controlled experimental laboratory set up as proposed. This review proffers an insight into the interactions of electrochemical and mechanical conditions of the different parameters, which govern the behavior of tribocorrosion systems. The emergence of the combined study on tribocorrosion for automotive component parts provides a methodological study to evaluate the combined behaviour based on the mechanical and synergistic effect occurring simultaneously on the automotive material in biodiesel. It was found from the study that synergism of wear and corrosion play an important role on the performance of biodiesel. Finally, it is expected that the theoretical model and proposed model set up for biodiesel biocompatible with automotive engine component materials will enhance the reliability and performance.

Simulation of wear map for biodiesel interacted automotive materials

“…occurs during sliding of the mating surfaces. Oxidation of the moving motor component reacts with biodiesel, which facilitates wear and friction [6]. When the behavior of metals used in automobiles is examined with biodiesel, it is observed that stainless steel is more resistant than copper and aluminum [7].…”

“…The accuracy of the path followed and the method of test directly affects the accuracy of the result. Many different test methods and laboratory setups have been suggested in previous studies [6,11]. However, in order to achieve more accurate results, the innovations to wear models can contribute to the work in this area.…”

Improved Tribocorrosion Resistance by Addition of Sn to CrFeCoNi High Entropy Alloy

“…where K [1,20] is the specific wear rate in mm 3 /N•m; V is the wear volume of material loss in mm 3 ; L is normal load in N and d is the total sliding distance in m; T [21] is the total material loss rate in mm/year; W c and C w are the total material loss due to mechanical wear and the total material loss due to corrosion, respectively; W 0 is the mechanical wear in absence of corrosion calculated from wear tests at cathodic potential; C 0 is the corrosion material loss rate in the absence of wear, which is normally treated as being negligible for passive metals and alloys; ∆W c is the change in wear rate due to corrosion in mm/year, and ∆C w is the change in corrosion rate due to wear in mm/year. Thus, T in tribocorrosion can be expressed as in Equation 5.…”

“…where T, W 0 [22] is the wear rate in mm/year; SA is the surface area of the wear track; t is the test time; k is a constant (3.27 × 10 −3 ) in mm•g/µA.cm.year; i ωt is the flowing current from wear track during abrasion in µA/cm 2 ; M is the equivalent weight (22.55 g/mol for CrFeCoNi and 28.68 g/mol for CrFeCoNiSn) which was calculated according to the ASTM G102-89 standard [19], and ρ is the density (8.20 g/cm 3 for CrFeCoNi and 8.44 g/cm 3 for CrFeCoNiSn) measured using MS104S/01 NewClassic MF density balance equipment (Mettler Toledo, Greifensee, Switzerland). The driving force for this material loss is the galvanic couple that forms between the depassivated surface (wear track) and the still passivated one (the rest of the surface).…”

“…Development of the tribocorrosion properties of materials is essential to meet the needs of a number of advanced applications, for example, biodiesel engines, pipe conveyor, and marine energy devices [1][2][3][4][5]. The principal material requirements that apply in such areas are a high potential to resist both corrosion and wear [1,5], as under service materials will be frequently exposed to chemically corrosive fluids (possibly under flow) and the friction load from wear interaction.…”