The influence of antiwear additive concentration on the tribological behaviour of a-C:H:W/steel tribosystem

Abstract

The effect of antiwear (AW) commercial additive concentration on the load-carrying capacity (scuffing resistance) of a-C:H:W/steel tribo-system intended for heavy-loaded machine parts was investigated. For comparison, steel/steel contacts were also investigated. The scuffing resistance has been measured as the limiting pressure of seizure ( poz) using the four-ball apparatus. The method with continuously increasing load was applied. The tribo-systems were lubricated with poly-alpha-olefin as base oil mixed with a commercial zinc dialkyldithiophosphates type of AW additive. The AW concentration was varied in the range of 0.1–5.0 wt%. The results of the tribological experiments performed in sliding contact have shown that, by the application of the a-C:H:W coating, the tribological properties of the system were significantly improved compared with the steel friction pairs. It has also been found that it is possible to reduce the concentration of commercial AW additive below 1.0 wt%. The surface topography of the rubbed surface was investigated with optical microscopy and atomic force microscopy; the elemental chemical nature of the AW film generated on the steel counter-surface (a-C:H:W/steel tribosystem) was investigated with energy dispersive spectrometry, glow discharge optical emission spectrometry, and X-ray photoelectron spectroscopy.

Efficient Visible‐Light‐Driven Hydrogen Generation on g‐C3N4 Coupled with Iron Phosphide

“…As shown in Figure 3C, the peak at 706.3 eV attributes to Fe δ + in bulk Fe 2 P and hybrid Fe 2 P, [23] demonstrating the presence of Fe 2 P. The other peak at 713.4 eV is assigned to Fe bound to phosphate. [24] From the P 2p peak ( Figure 3D), the typical peak at 129.4 eV is assigned to P δÀ species in metal phosphide. [25] The other binding energy of 133.8 eV can be associated with P in phosphates.…”

The potential of the application of biodegradable and non‐toxic base oils for the formulation of gear oils — model and component scuffing tests

“…Because the potential market for ecological lubricants seems to be wide and because new EU regulations imposing the application of biodegradable lubricants in selected areas of technique can be expected, many researchers have undertaken an effort to develop ecological lubricants. They include ecological oils, greases and cutting fluids; however, there is also a new approach related to the reduction of the content of toxic additives in lubricants by the application of scuffing‐preventive hard, thin coatings on the mating machine parts …”

“…They include ecological oils, greases and cutting fluids [3][4][5][6][7] ; however, there is also a new approach related to the reduction of the content of toxic additives in lubricants by the application of scuffing-preventive hard, thin coatings on the mating machine parts. 8 The aim of this work was to assess natural and white oils as potential candidate bases of gear oils. To this end, scuffing tests, i.e.…”

The problems of resistance to scuffing of heavily loaded lubricated friction joints with WC/C-coated parts

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