The Adsorption and Reaction of Decomposition Products of Zinc Di-Isopropyldiophosphate on Steel

Bovington, C. H.; Dacre, B.

doi:10.1080/05698198408981568

Cited by 45 publications

(16 citation statements)

References 5 publications

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“…In the non-contact areas at 30°C and 80°C, only very thin reaction layers of zinc sulphide and zinc phosphate were formed, whereas the films at 80°C were thicker. This is in agreement with earlier temperature-dependent studies [11] and according to Bovington and Dacre, the thermal decomposition starts at 60°C in the presence of iron powder as a catalyst [67]. At 150°C, thick thermal films made of long-chain poly(thio)phosphate were formed, due to thermo-oxidative processes [3,11,29,70].…”

Section: Off-contact Areasupporting

confidence: 80%

“…Under mechanical stress, there are further potential pathways: Wear might have removed the thermal layer, formed prior to contact, and upon tribostress a similar film-formation mechanism as at lower temperatures takes place [66]. Alternatively iron oxide reacts with the poly(thio)phosphates causing a shortening of the chains [67]. Iron is known to function as a depolymerising element for phosphate glasses [62].…”

Section: Influence Of Contact Pressure On Thickness and Composition Omentioning

confidence: 99%

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Pressure Dependence of ZnDTP Tribochemical Film Formation: A Combinatorial Approach

2007

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Combinatorial testing has been performed on zinc dialkyldithiophosphate (ZnDTP)-containing lubricants, to investigate the effects of contact pressure on the formation of tribochemical films. Contact pressures ranging from 25 to 500 MPa were applied in ball-on-disc tribotests with oscillating load. Both the ball and the disc were investigated by means of small-area and imaging X-ray photoelectron spectroscopy (XPS). The thickness and the composition of the reaction layer were estimated from the XPS data. The thickness of the reaction layer in the tribologically stressed areas of the ball and of the disc increased with both temperature and contact pressure. The reaction layer mainly consisted of short-chain poly(thio)phosphates, shorter chains being observed at higher contact pressures. At high pressures, the presence of a thick, high-toughness short-chain poly(thio)phosphate layer can explain the lower friction and dimensional wear coefficients observed. On the ball, similar anti-wear film formation mechanisms were observed as on the disc, zinc sulphide being deposited in the post-contact region.

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Section: Off-contact Areasupporting

confidence: 80%

Section: Influence Of Contact Pressure On Thickness and Composition Omentioning

confidence: 99%

Pressure Dependence of ZnDTP Tribochemical Film Formation: A Combinatorial Approach

2007

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“…These factors include strong dipole interactions or strong hydrogen bonding which aid physical adsorption and the ease of chemical reaction from this adsorbed layer. Both interactions favour the formation of low-shear-strength films and similar influences have been reported by many workers including wear for mixtures of dilinoleic and linoleic acids [11], and for ZDDPs [6].…”

Section: Influence Of Metal Surfacesmentioning

confidence: 60%

“…But once θ falls below this critical value, believed to be approx 0.5, friction and wear will rise. The adsorption of dilinoleic acid [4], a series of organic sulphur compounds [5] and a ZDDP (zinc dialkyldithiophosphate) [6] has been described in these terms.…”

Section: Formation Of Surface Filmsmentioning

confidence: 99%

Friction, Wear and the Role of Additives in Controlling Them

Bovington

2009

Chemistry and Technology of Lubricants

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The laws of friction are described. Abrasive, adhesive, contact fatigue and corrosive wear mechanisms are explained. The tribological regime of boundary lubrication is discussed in the context of the Stribeck curve and surface film formation. Physical processes for surface film formation and their properties are examined for oxygen-, nitrogen-, sulphur-, phosphorus, boron, molybdenum-containing organic compounds and ZDDP in particular. ZDDP film formation is discussed in depth and the influence of dispersants described. Interactions between reduced ZDDP levels and molybdenum compounds to maintain wear protection and antioxidancy are considered for the requirements of lower SAPS formulations in future formulations.

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“…The literature regarding the composition and formation of ZDDP derived antiwear films for hardened steel on hardened steel is extensive and controversial. One mechanism of film formation views that ZDDP adsorbs onto the metal surfaces and then undergoes decomposition at the rubbing surfaces to form the protective film [6][7][8]. Another, perhaps more widely held view of the mechanism of film formation holds that ZDDP decomposes in oil, and that it is these decomposition products which react with the rubbing surfaces to form the protective film [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

X-ray absorption spectroscopy of antiwear films on aluminum alloys generated from zinc dialkyldithiophosphate

et al. 1995

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The boundary lubrication of A1 alloys 6061 (AI-6% Si) and A-390 (Al-18 wt% Si), by a sec-ZDDP (zinc dialkyldithiophosphate) oil blend was examined at 60 andl00~ The wear performance in the ZDDP blend was an improvement on base stock. At 100~ the ZDDP prevented scuffing, though no antiwear films could be detected due to the severe wear. At 60~ all samples showed initial scuffing followed by a more controlled wear given by an embedded antiwear film. P L-edge X-ray near-edge structure (XANES) spectroscopy using synchroton radiation was used to characterize the antiwear and thermally generated deposition films on the A1 alloys. P L-edge XANES results of the antiwear films at 100~ showed the absence of a polyphosphate film. A well-developed polyphosphate film was indicated at 60~ very similar to that formed on steel at 100~ P L-edge XANES results of the thermal deposition films showed the presence of only unchanged sec-ZDDP at 125~ with no polyphosphate present. A polyphosphate film was present at 200~ similar to the antiwear film for A1 alloy at 60~ and steel at 100~

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The Adsorption and Reaction of Decomposition Products of Zinc Di-Isopropyldiophosphate on Steel

Cited by 45 publications

References 5 publications

Pressure Dependence of ZnDTP Tribochemical Film Formation: A Combinatorial Approach

Pressure Dependence of ZnDTP Tribochemical Film Formation: A Combinatorial Approach

Friction, Wear and the Role of Additives in Controlling Them

X-ray absorption spectroscopy of antiwear films on aluminum alloys generated from zinc dialkyldithiophosphate

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