Synergistic and Competitive Effects between Zinc Dialkyldithiophosphates and Modern Generation of Additives in Engine Oil

Abstract

The increasing demand for low-viscosity engine oil has underscored the role of zinc dialkyldithiophosphates (ZDDP) as a conventional anti-wear and antioxidant additive. It is essential to investigate the influence of modern additives such as cyclopropanecarboxylic acid (CPCa) and Ni nanoparticles on the tribological performance of ZDDP for practical commercial oil application. According to the experimental results, Ni nanoparticles formed a protective film that exhibited a synergistic effect with ZDDP. A significantly higher concentration of sulphur in the tribofilm was detected compared to ZDDP by itself, which was responsible for a 27.6% lower wear loss. Meanwhile, a competitive effect between CPCa and ZDDP resulted in a dramatic increase in friction and unstable anti-wear performance. This was demonstrated by a localized formation of the ZDDP tribofilm on the wear surfaces after the friction test. These results have highlighted the synergistic and competitive effects of emerging additives (CPCa and Ni nanoparticles) in the ZDDP tribofilm formation between the sliding steel contacts. This further suggests a new approach to increase the efficiency of ZDDP’s tribological performance at cold start-up processes.

Tribochemical Interactions between Graphene and ZDDP in Friction Tests for Uncoated and W-DLC-Coated HS6-5-2C Steel

“…The tribological tests were carried out using a TRB 3 tribometer. The ball-on-disc configuration operated at a humidity of 37 ± 15% and an ambient temperature (T 0 ) of 24 ± 4 • C. The test parameters were as follows: load 10 N, sliding speed 0.1 m/s and sliding distance 1000 m.…”

“…One of the most common lubricant additives is zinc dialkyldithiophosphate, ZDDP, added, for instance, to engine oils. Originally, in 1940 [3], it was developed as an antioxidant and detergent [4]; its other potential applications were suggested later [3]. In the literature, ZDDP is classified as an antiwear and anticorrosion additive [5].…”

Effect of an Aftermarket Additive in Powertrain Wear and Fuel Consumption of Small-Capacity Motorcycles: A Lab and Field Study

“…Surprisingly, to the best of the authors' knowledge, there was no peer-reviewed reference about MC performance in powertrains, even though that is its primary application. Contrastingly, there are thousands of papers evaluating the performance of base or fully formulated oils with the addition of additives or nanoparticles using standardized and tribological tests [11,[18][19][20][21][22]. Although lab tests (pin-on-disk, four-ball, copper corrosion, etc.)…”

“…Although lab tests (pin-on-disk, four-ball, copper corrosion, etc.) provide evidence and insights into lubricants' performance, it is challenging to evaluate engine conditions in the laboratory [18,22,23]. In fact, it has been shown that elaborate tests fail to reproduce the tribofilms observed in engine parts [18,21].…”

“…In fact, it has been shown that elaborate tests fail to reproduce the tribofilms observed in engine parts [18,21]. Furthermore, lab tests often do not evaluate lubricant degradation over time and its impact on system performance [22]. This situation is aggravated for motorcycle engines since in this application the oil also lubricates the gearbox and the clutch [12,13,24].…”