Publications
170 results found
SPIKES HA, CANN PM, 1990, THE INFLUENCE OF SLIDING SPEED AND LUBRICANT SHEAR-STRESS ON EHD CONTACT TEMPERATURES, TRIBOLOGY TRANSACTIONS, Vol: 33, Pages: 355-362, ISSN: 1040-2004
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- Citations: 8
Wardle RWM, Coy RC, Cann PM, et al., 1990, An ‘in lubro’ study of viscosity index improvers in end contacts, Lubrication Science, Vol: 3, Pages: 45-62, ISSN: 0954-0075
Polymeric viscosity index (VI) improver solutions in oils suffer from both temporary and permanent viscosity losses in high shear hydrodynamic and elastohydrodynamic (EHD) contacts. In some cases in EHD contacts, these losses can be so severe that the additive makes negligible contribution to oil film thickness. This paper describes the use of a combination of optical interferometry and FTIR micro‐reflectance spectroscopy to measure the effectiveness, and to observe directly the behaviour, of conventional VI improver solutions within rolling and sliding EHD contacts. The study shows the extent to which polymers enter EHD contacts and charts the degradation that they suffer therein. Copyright © 1990 John Wiley & Sons, Ltd
CANN PM, SPIKES HA, 1989, DETERMINATION OF THE SHEAR STRESSES OF LUBRICANTS IN ELASTOHYDRODYNAMIC CONTACTS, TRIBOLOGY TRANSACTIONS, Vol: 32, Pages: 414-422, ISSN: 0569-8197
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- Citations: 26
Cann PME, Johnston GJ, Spikes HA, 1987, FORMATION OF THICK FILMS BY PHOSPHORUS-BASED ANTI-WEAR ADDITIVES., Pages: 543-554, ISSN: 0144-0799
Phosphorus-containing esters are widely used as additives in lubricating oils to reduce wear of rubbing steel surfaces. Recent work has suggested that these additives function by forming a protective layer on the rubbing surfaces, of the order of the surface roughness in thickness. This layer can be a rigid polymeric solid but in some cases appears to be material weakly bonded to the metal surfaces and easily rubbed off. The enhanced viscosity of this material relative to that of bulk oil appears to ensure surface separation by elastohydrodynamic means even at high temperatures where the viscosity of the bulk oil is very low. This paper provides experimental support for the existence of thick anti-wear films for a range of phosphorous esters and discusses their structure, mechanism of formation and practical implications.
Cann PM, Spikes HA, 1987, The influence of lubricant on temperature generated in elasto-hydrodynamic contacts., Tribology Series, Vol: 12, Pages: 183-192, ISSN: 0167-8922
Direct measurement of temperatures generated in concentrated contacts by infra-red (IR) radiometry can be used to explore the rheological properties of lubricants under elastohydrodynamic (EHD) conditions. This paper describes the influence of lubricant composition on thermal effects in EHD and attempts to relate rheological characteristics of the fluids to the temperature produced. The lubricants have been chosen to provide a range of rheological and chemical properties. They include synthetic hydrocarbons, polyglycols, perfluorethers, and a traction fluid. An emission technique similar to that employed by Winer and coworkers (1976) has been used to measure the surface temperature distribution within an EHD contact. Significant differences have been found between the surface temperature response of these fluids. The role of lubricant rheology in determining temperature with EHD contacts is discussed together with the implications of such measurement in the study of the traction response of lubricants.
Cann PME, Johnston GJ, Spikes HA, 1987, The formation of thick films by phosphorous-based anti-wear additives., IN: PROC. IMECHE INT. CONF. ON TRIBOLOGY - FRICTION, LUBRICATION AND WEAR, FIFTY YEARS ON, (LONDON, U.K.: JUL. 1-3, 1987), Vol: I, Bury St Edmunds, U.K., Mech. Engng. Publications Ltd., 1987, Paper C208/87, Pages: 543-554
Phosphorus containing esters are widely used as additives in lubricating oils to reduce wear of rubbing steel surfaces. Recent work has suggested that these additives function by forming a protective layer on the rubbing surfaces, of the order of the surface roughness in thickness. This layer can be a rigid polymeric solid but in some cases appears to be material weakly bonded to the metal surfaces and easily rubbed off. The enhanced viscosity of this material relative to that of bulk oil appears to ensure surface separation by elastohydrodynamic means even at high temperatures where the viscosity of the bulk oil is very low. This paper provides experimental support for the existence of thick antiwear films for a range of phosphorous esters and discusses their structure, mechanism of formation and practical implications. (A)
Cann PM, Spikes HA, 1987, The influence of lubricant on temperature generated in elasto-hydrodynamic contacts.
Direct measurement of temperatures generated in concentrated contacts by infra-red (IR) radiometry can be used to explore the rheological properties of lubricants under elastohydrodynamic (EHD) conditions. This paper describes the influence of lubricant composition on thermal effects in EHD and attempts to relate rheological characteristics of the fluids to the temperature produced. The lubricants have been chosen to provide a range of rheological and chemical properties. They include synthetic hydrocarbons, polyglycols, perfluorethers, and a traction fluid. An emission technique similar to that employed by Winer and coworkers (1976) has been used to measure the surface temperature distribution within an EHD contact. Significant differences have been found between the surface temperature response of these fluids. The role of lubricant rheology in determining temperature with EHD contacts is discussed together with the implications of such measurement in the study of the traction response of lubricants.
Johnston G, Cann PM, Spikes HA, 1986, Phosphorus anti-wear additives: thick film formation and its influence on surface distress.
It has recently been shown, using optical interferometry, that phosphonate ester antiwear additives form thick polymeric films in rolling elastohydrodynamic contacts. This paper uses interferometric and electrical contact resistance techniques to demonstrate that similar films develop in contacts under conditions of sliding, and, initially, boundary lubrication. Discussion of this paper is included on p.157-158. (A)
Johnston G, Cann PME, Spikes HA, 1986, A new mechanism for gear and bearing anti-wear additive behaviour., IN: 5TH INT. COLLOQUIUM ON ADDITIVES FOR LUBRICANTS AND OPERATIONAL FLUIDS, (OSTFILDERN, FED. REP. GERMANY: JAN. 14-16, 1986), Vol: 1 , Ostfildern, Fed. Rep. Germany, Esslingen Tech. Akad., 1986, Session 3, Paper 3.12, p.3.12-1-3.12-1
Work was carried out to examine the formation of thick films on rubbed metal surfaces by phosphorous containing antiwear additives. These investigations provide ample evidence that films over a hundred nanometers thick can form on surfaces from ZDDP and phosphonate ester solutions and separate surfaces by this amount in rolling and sliding conditions. (from paper)
Johnston G, Cann PM, Spikes HA, 1986, Phosphorus anti-wear additives: thick film formation and its influence on surface distress.
It has recently been shown, using optical interferometry, that phosphonate ester antiwear additives form thick polymeric films in rolling elastohydrodynamic contacts. This paper uses interferometric and electrical contact resistance techniques to demonstrate that similar films develop in contacts under conditions of sliding, and, initially, boundary lubrication. Discussion of this paper is included on p.157-158. (A)
Cann P, Spikes HA, Caporiccio G, 1984, Spreading of perfluorinated fluids on metal surfaces.
Of the theoretical models reviewed the kinetic analysis of Lopez, Miller and Ruckstein would appear to offer a satisfactory model for the spreading of perfluropolyether lubricants and silicones. The spreading of drops in the 'gravity-viscous' regime was monitored and the results are in reasonable agreement with theoretical predictions. Spreading gradients of 0.097-0.2 were measured compared to a theoretical slope of 0.125. The slope was also found to be invariant with drop volume, but not with fluid viscosity. The second result is contrary to prediction, and may result from an intermolecular force contribution to spreading. Support for the theory that drops can experience successive regimes of spreading is provided by the observation that the spreading gradient of some low viscosity fluids increase as spreading proceeeds. The formation of a ridge near the spreading edge was also observed. This was considered to be due to the predominance of intermolecular forces. Tests on an experimental fluid show that minor modifications in composition can lead to a great increase of spreading rates. (from paper)
Cann P, Spikes HA, Caporiccio G, 1984, Spreading of perfluorinated fluids on metal surfaces.
Of the theoretical models reviewed the kinetic analysis of Lopez, Miller and Ruckstein would appear to offer a satisfactory model for the spreading of perfluropolyether lubricants and silicones. The spreading of drops in the 'gravity-viscous' regime was monitored and the results are in reasonable agreement with theoretical predictions. Spreading gradients of 0.097-0.2 were measured compared to a theoretical slope of 0.125. The slope was also found to be invariant with drop volume, but not with fluid viscosity. The second result is contrary to prediction, and may result from an intermolecular force contribution to spreading. Support for the theory that drops can experience successive regimes of spreading is provided by the observation that the spreading gradient of some low viscosity fluids increase as spreading proceeeds. The formation of a ridge near the spreading edge was also observed. This was considered to be due to the predominance of intermolecular forces. Tests on an experimental fluid show that minor modifications in composition can lead to a great increase of spreading rates. (from paper)
Spikes HA, Cann P, Caporiccio G, 1984, Elastohydrodynamic film thickness measurements of perfluoropolyether fluids.
The EHD film thickness properties of various perfluoropolyether lubricants were measured using optical interferometry. From these results, calculated pressure/viscosity coefficients were calculated. Perfluorinated polyethers derived from hexafluoropropene have high pressure/viscosity coefficients, in the range 28-36 GPa SUP - SUP 1. Perfluorinated polyethers derived from tetrafluroethane have lower pressure viscosity coefficients, in the range 4-12 GPa SUP - SUP 1. (from paper)
Cann P, Spikes H, 1984, Determination of oil films on lubricated surfaces.
It is often important in tribology to be able to determine the thickness of lubricant on surfaces before and after rubbing. This paper describes a method of measuring oil film thickness in the range 20-1000 nm using reflection infrared spectroscopy. Results for some practical applications are included and their implications are discussed. (A)
Cann P, Spikes H, 1984, DETERMINATION OF OIL FILMS ON LUBRICATED SURFACES., Pages: 79-82
It is often important in Tribology to be able to determine the thickness of lubricant on surfaces before and after rubbing. This paper describes a method of measuring oil film thickness in the range 20-1000nm using reflection infrared spectroscopy. Results for some practical applications are included and their implications are discussed.
Spikes HA, Cann P, Caporiccio G, 1984, Elastohydrodynamic film thickness measurements of perfluoropolyether fluids, Journal of Synthetic Lubrication, Vol: 1, Pages: 73-86, ISSN: 0265-6582
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- Citations: 26
Cann P, Spikes H, 1984, Determination of oil films on lubricated surfaces.
It is often important in tribology to be able to determine the thickness of lubricant on surfaces before and after rubbing. This paper describes a method of measuring oil film thickness in the range 20-1000 nm using reflection infrared spectroscopy. Results for some practical applications are included and their implications are discussed. (A)
Spikes HA, Cann P, Caporiccio G, 1984, Elastohydrodynamic film thickness measurements of perfluoropolyether fluids.
The EHD film thickness properties of various perfluoropolyether lubricants were measured using optical interferometry. From these results, calculated pressure/viscosity coefficients were calculated. Perfluorinated polyethers derived from hexafluoropropene have high pressure/viscosity coefficients, in the range 28-36 GPa SUP - SUP 1. Perfluorinated polyethers derived from tetrafluroethane have lower pressure viscosity coefficients, in the range 4-12 GPa SUP - SUP 1. (from paper)
CANN P, CAMERON A, 1984, STUDIES OF THICK BOUNDARY LUBRICATION - INFLUENCE OF ZD DP AND OXIDIZED HEXADECANE, TRIBOLOGY INTERNATIONAL, Vol: 17, Pages: 205-208, ISSN: 0301-679X
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- Citations: 10
CANN P, SPIKES HA, CAMERON A, 1983, THICK-FILM FORMATION BY ZINC DIALKYLDITHIOPHOSPHATES, ASLE TRANSACTIONS, Vol: 26, Pages: 48-52, ISSN: 0569-8197
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- Citations: 15
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