Publications
472 results found
Cann P, Spikes HA, Cameron A, 1983, Thick Film Formation by Zinc Dialkyldithiophosphates, A S L E Transactions, Vol: 26, Pages: 48-52, ISSN: 0569-8197
Stinton HC, Spikes HA, Cameron A, 1982, A study of friction polymer formation, ASLE Transactions, Vol: 25, Pages: 355-360, ISSN: 0569-8197
Surfactant solutions in hexadecane have been studied to assess their capabilities in forming friction polymer. Only alcohols form adherent films, resistant to simple washing, on rubbing surfaces. There is no evidence of polymer formation on rubbed surfaces, even with mixtures of diacids and diols. © 1982 Taylor & Francis Group, LLC.
Spikes H, Macpherson PB, 1981, The design, formulation and testing of a new type of lubricant for helicopter gearboxes., IN: PROC. INT. SYMP. ON PERFORMANCE AND TESTING OF GEAR OILS AND TRANSMISSION FLUIDS, (LONDON, U.K.: OCT. 1980), R. TOURRET;
A three-year programme carried out at Imperial College to develop a new helicopter gearbox oil is oulined. The purpose of presenting it is to show that such a development can be completed successfully in a small laboratory without recourse to the expertise and resources of a major oil manufacturer so long as two requirements are met. These are, first, a full understanding of the limitations and weaknesses of existing oils and, second, a carefully chosen sequence of testing methods designed to match the proposed oil application. The most promising of the candidate oils formulated by the procedures outlined has been subjected to rigorous gearbox evaluation and has been found to perform satisfactorily. (from paper)
Spikes H, Macpherson PB, 1981, The design, formulation and testing of a new type of lubricant for helicopter gearboxes., IN: PROC. INT. SYMP. ON PERFORMANCE AND TESTING OF GEAR OILS AND TRANSMISSION FLUIDS, (LONDON, U.K.: OCT. 1980), R. TOURRET;
A three-year programme carried out at Imperial College to develop a new helicopter gearbox oil is oulined. The purpose of presenting it is to show that such a development can be completed successfully in a small laboratory without recourse to the expertise and resources of a major oil manufacturer so long as two requirements are met. These are, first, a full understanding of the limitations and weaknesses of existing oils and, second, a carefully chosen sequence of testing methods designed to match the proposed oil application. The most promising of the candidate oils formulated by the procedures outlined has been subjected to rigorous gearbox evaluation and has been found to perform satisfactorily. (from paper)
Spikes HA, Hammond CJ, 1981, The Elastohydrodynamic Film Thicknesses of Binary Ester-Ether Mixtures, A S L E Transactions, Vol: 24, Pages: 542-548, ISSN: 0569-8197
HILEY RW, SPIKES HA, CAMERON A, 1981, POLYSULFIDES AS EXTREME-PRESSURE LUBRICANT ADDITIVES, LUBRICATION ENGINEERING, Vol: 37, Pages: 732-737, ISSN: 0024-7154
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Newley RA, Spikes HA, Macpherson PB, 1980, Oxidative Wear in Lubricated Contact, Journal of Lubrication Technology, Vol: 102, Pages: 539-544, ISSN: 0022-2305
<jats:p>Lubricant antioxidant additives are known to reduce fretting wear. Wear tests have been carried out in association with chemical analyses of the test lubricant to elucidate the mechanism of oxidative wear. It is shown that the rate of wear is not directly related to the concentration in the lubricant of either acids or peroxides. It is proposed that the metal is oxidized by reacting with peroxy radicals which form as intermediates as the lubricant is oxidized. The reduction of wear in the presence of antioxidants is a result of the elimination of these radicals by the additive.</jats:p>
Hiley RW, Nat Gas Turbine Establ, Spikes HA, et al., 1980, Polysulfides as extreme pressure lubricant additives., IN: AM. SOC. LUBR. ENGRS. TECH. PREPRINTS, PRESENTED TO ASME/ASLE INT. LUBR. CONF., (SAN FRANCISCO, U.S.A.: AUG. 18-21, 1980)
Two series of polysulfides containing from one to four sulphur atoms have been synthesized and their extreme-pressure, antiwear and corrosion properties measured. Both E.P. and antiwear performance improve as sulphur chain length increases. A semiempirical law to predict EP performance has been proposed and it has been shown that the antiwear behaviour observed does not conform to current theories of polysulphide antiwear action. Commercially available sulphurized EP additives have been separated using thin-layer chromatography. (A)
Hiley RW, Nat GTE, Spikes HA, et al., 1980, Polysulfides as extreme pressure lubricant additives., IN: AM. SOC. LUBR. ENGRS. TECH. PREPRINTS, PRESENTED TO ASME/ASLE INT. LUBR. CONF., (SAN FRANCISCO, U.S.A.: AUG. 18-21, 1980)
Two series of polysulfides containing from one to four sulphur atoms have been synthesized and their extreme-pressure, antiwear and corrosion properties measured. Both E.P. and antiwear performance improve as sulphur chain length increases. A semiempirical law to predict EP performance has been proposed and it has been shown that the antiwear behaviour observed does not conform to current theories of polysulphide antiwear action. Commercially available sulphurized EP additives have been separated using thin-layer chromatography. (A)
Spikes HA, Hammond CJ, 1980, The elastohydrodynamic film thicknesses of binary ester-ether mixtures., IN: AM. SOC. LUBR. ENGRS. TECH. PREPRINTS, PRESENTED TO ASME/ASLE INT. LUBR. CONF., (SAN FRANCISCO, U.S.A.: AUG.18-21, 1980)
Mixtures of various proportions of a polyolester and a polyphenylether (5P4E) have been prepared and their elastohydrodynamic film thicknesses measured in a rolling point contact. It has been found that small amounts of polyolester reduce the film thickness of 5P4E far more than viscosity values would predict. One explanation for this is that the pressure-viscosity coefficient of 5P4E is very sensitive to small amounts of polyolester, and is reduced by a factor of five with only 20 percent of polyolester. This might result from the ester acting as a plasticizer in reducing the glass transition temperature of 5P4E. Alternatively, 5P4E may be behaving in a non-Newtonian fashion over the range of shear rates studied. (A)
Spikes HA, Macpherson PB, 1980, Water content of helicopter gear oil., ISSN: 0402-1215
The disolved water contents of a number of gearbox lubricants were measured in laboratory experiments, fatigue test rigs and helicopter test and service gearboxes. The effect of temperature and humidity on water content was determined. It was concluded that the water levels present in test and service gearboxes may be sufficient to reduce rolling fatigue lives. A comparison of water content in fatigue test rigs and service gearboxes showed that differences exist between the two which may impair correlations of fatigue lives. (A)
Spikes HA, Macpherson PB, 1980, WATER CONTENT OF HELICOPTER GEAR OILS., American Society of Mechanical Engineers (Paper), ISSN: 0402-1215
The dissolved water contents of a number of gearbox lubricants have been measured in laboratory experiments, fatigue test rigs and helicopter test and service gearboxes. The effect of temperature and humidity on water content has been determined. It is concluded that the water levels present in test and service gearboxes may be sufficient to reduce rolling fatigue lives. A comparison of water content in fatigue test rigs and service gearboxes shows that differences exist between the two which may impair correlations of fatigue lives.
Spikes HA, Hammond CJ, 1980, The elastohydrodynamic film thicknesses of binary ester-ether mixtures., IN: AM. SOC. LUBR. ENGRS. TECH. PREPRINTS, PRESENTED TO ASME/ASLE INT. LUBR. CONF., (SAN FRANCISCO, U.S.A.: AUG.18-21, 1980)
Mixtures of various proportions of a polyolester and a polyphenylether (5P4E) have been prepared and their elastohydrodynamic film thicknesses measured in a rolling point contact. It has been found that small amounts of polyolester reduce the film thickness of 5P4E far more than viscosity values would predict. One explanation for this is that the pressure-viscosity coefficient of 5P4E is very sensitive to small amounts of polyolester, and is reduced by a factor of five with only 20 percent of polyolester. This might result from the ester acting as a plasticizer in reducing the glass transition temperature of 5P4E. Alternatively, 5P4E may be behaving in a non-Newtonian fashion over the range of shear rates studied. (A)
Hamaguchi H, Spikes HA, Cameron A, 1977, Elastohydrodynamic properties of water in oil emulsions, Wear, Vol: 43, Pages: 17-24, ISSN: 0043-1648
Spikes HA, 1974, ADDITIVE INTERFERENCE IN DIBENZYL DISULFIDE EXTREME PRESSURE LUBRICATION., ASLE Trans, Vol: 17, Pages: 283-289
A series of very simple radioactive chemical tests has been carried out to measure reaction of dibenzyl disulfide on steel. By comparing the results with friction experiments under the same conditions, some of the requirements of extreme pressure lubrication have been determined. Current views on the mechanism of reactions of dibenzyl disulfide have been confirmed and it has been demonstrated that only a thin EP film is needed to give boundary lubrication. In particular, an important additive interference effect has been noted between extreme pressure activity and high temperature detergents.
, 1974, A comparison of adsorption and boundary lubricant failure, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, Vol: 336, Pages: 407-419, ISSN: 0080-4630
<jats:p>A comparison has been made between the reversible adsorption and the friction-reducing properties of long-chain fatty amines on stainless steel. This has shown that adsorption and lubricant failure depend on concentration of amine and temperature in a similar way. Breakdown of lubrication may therefore be associated with reversible desorption of amines from steel surfaces. Measurement of the adsorption properties of the fatty amines indicates a lowering of the isosteric heat of adsorption at low temperatures, which may result from ‘pre-freezing’ of the hydrocarbon solvent.</jats:p>
Spikes HA, 1974, The action of oil additives
This article is part of a review report on the background to current theories of scuffing. An introduction is given to extreme pressure additives. The use of sulphur-containing additives, and methods of investigating extreme pressure activity are discussed. The effect of temperature on E.P. films and their lubricating properties, and the effect of sliding load and speed on E.P. activity are discussed in relation to previous work in this field. Anti-wear and anti-seizure effects are mentioned. The mechanisms of E.P. additive action and additive interference are summarised. A literature review is presented. (V.B.D.)
Spikes HA, Cameron A, 1974, Scuffing as a desorption process—An explanation of the borsoff effect, ASLE Transactions, Vol: 17, Pages: 92-96, ISSN: 0569-8197
The hypothesis that scuffing of surfaces lubricated by a plain mineral oil results from desorption is tested for high speed cases using two types of apparatus. One uses a medium speed, 1-inch steel ball, 4-ball machine, and a simulated oil consisting of hexadecanoic acid in hexadecane. This lubricant is shown to behave in the same fashion at medium speeds as it does at very slow speeds. Thus, a graph of logarithmic concentration of acid against reciprocal absolute scuffing temperature gives a good straight line, just as at slow speeds. In the second high speed gear tester, the rise in scuff load of gears at very high speeds, the Borsoff effect, can be explained semiquantitatively by considering the residence time of molecules. These two types of results suggest that the desorption-failure mechanism may be valid over the whole rubbing speed range, and not merely at the very low speeds normally tested. © 1974 Taylor & Francis Group, LLC.
Spikes HA, Cameron A, 1974, Scuffing as a Desorption Process—An Explanation of the Borsoff Effect, A S L E Transactions, Vol: 17, Pages: 92-96, ISSN: 0569-8197
Spikes HA, Cameron A, 1974, Additive Interference in Dibenzyl Disulfide Extreme Pressure Lubrication, A S L E Transactions, Vol: 17, Pages: 283-289, ISSN: 0569-8197
SPIKES HA, 1972, Physical and chemical adsorption in boundary lubrication
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