Insights into the tribological behavior of IF-WS₂ nanoparticle reinforced mild extreme pressure lubrication for coated chromium/bulk grey cast iron interface

Abstract

This study reports a novel synergetic approach combining nano-lubrication and conventional extreme pressure additivation, to explore the tribological performance of piston ring/cylinder liner conformal contact. Three typical lubricating formulations, viz, (i) PAO (poly-alpha-olefin) base oil (ii) base oil with mild extreme pressure (MEP) additive, and (iii) base oil with composite blend of mild extreme pressure (MEP) additive and WS2 nano-particles, were investigated using an ASTM G-99 Standard customized universal tribometer for evaluating friction and wear behavior of coated chromium/bulk grey cast iron (CI) tribopair. The lubricant formulations were tested at engine working temperature of 200 °C, reciprocated under a normal load of 30 N, stroke length of 10 mm and a constant sliding velocity of 0.2 ms−1. Wear attributes were evaluated by employing non-contact based 3 D optical profilometry. For assessment of tribo-surface morphology and associated surface characterization, Elemental Dispersion Spectral (EDS) incorporated Scanning Electron Microscope (SEM) was utilised. Green Laser Raman spectroscopy investigated tribo-chemistry, synergetic interactions and tribo-film formations. A state approaching super-lubricity and ultralow friction was achieved by sliding grey CI (Plateau Honed) cylinder liner against electroplated chrome stainless steel top compression ring with PAO10 base oil ultrasonically dispersed with 1 vol% of Isopropyl phenyl Phosphate (IPP), a mild extreme pressure (MEP) triaryl phosphate additive & 1 wt.% of WS2. Results obtained therein demonstrated four dominating forms of wear on the cast iron surface, i.e. plowing wear, abrasive wear, adhesive wear and oxidative wear. Counterpart chromium surface exhibited plowing and abrasive wear only. This substantial friction and wear reduction are attributed to the coalesced intrinsic characteristics of MEP and IF-WS2 additives, thus improving the overall lubrication characteristics of base oil.

Unlocking the Potential of Soft Computing for Predicting Lubricant Elemental Spectroscopy

“…It is evident that the field of engine and lubricant research is vast, with a plethora of studies that have investigated diverse methods for enhancing performance and curtailing energy loss in internal combustion piston engines. These techniques encompass the use of lubrication quality [41], coatings [42], and multifarious tribological approaches [43]. Consequently, there exist multiple prospects for tackling lubricant and engine health concerns, and this academic inquiry delves into maintenance and management techniques that leverage the electrical properties of lubricants and neural networks.…”

Wear and Rolling Contact Fatigue Analysis of AISI 52100 Bearing Steel in Presence of Additivated Lubricants

“…The commercial mineral oils available in the markets consist of about 90-95% of base mineral oil and 5-10% of additives. With the demand for high-performance lubricants with enhanced tribological properties, the tribological properties of tungsten disulphide (WS 2 ) [4,5] and molybdenum disulphide (MoS 2 ) were investigated [6], which have been considered as efficient emergency extreme pressure solid lubricants in industries. The formation of a stable lubricant film by MoS 2 and other sulphates is the major reason for combating friction and wear [7].…”