摘要:

Paper chromatography has been used in combination with neutron activation analysis to analyze the polar lubricity additive zinc dihexyldithiophosphate. This additive is shown to contain small but significant quantities of both phosphorous and zinc-containing polar impurities. Results of lubricity tests suggest that these polar impurities are adsorbed preferentially on a metal surface and therefore are available for the lubrication reaction in preference to the zinc dihexyldithiophosphate molecule itself. An acid phosphate-type compound is believed to be the active polar impurity controlling the wear behavior of zinc dihexyldithiophosphate.

ISSN:0569-8197    

DOI:10.1080/05698197308982717

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Data are presented on the changes in the properties of a disiloxane/ester fluid resulting from water concentrations as small as 200 ppm while undergoing mechanical stress at 275 F in a simulated aircraft hydraulic system. The response of fluid flash point, viscosity, neutralization number, and hydraulic system filter differential pressure are discussed for hydraulic fluid water concentrations as high as 18,900 ppm. The efforts of previous investigators, employing bench tests and simulated systems, are reviewed. The limitations and sources of error of methods of determining fluid degradation and level of water contamination, as determined by this study, are noted. Attention is given to the importance of reacted water, for which no routine method of determination has been developed, as apposed to free water as determined by the Karl Fischer method of analysis.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

ISSN:0569-8197    

DOI:10.1080/05698197308982718

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The relative validity of the concepts of constant coefficient of friction (f) and constant interface friction shear factor (m) as quantitative indices for defining friction stresses existing in metal deformation operations has been investigated by means of the ring compression test technique. Material flow stress values have been determined by ring compression tests using mathematical formulae based upon both concepts in question. These have been compared with flow stress values obtained on the same material using the accurate Polakowski technique which is not based upon any mathematical concept, but which can only be carried out at ambient temperature and low strain rates. Flow stress values obtained by analyzing ring compression test results, using the concept of constant interface friction factor, were found to be consistently lower than the values obtained using the constant coefficient of friction concept, and in good agreement with results obtained using the Polakowski technique. For this reason, it has been concluded that the concept of constant interface shear factor (m) is the more realistic as a quantitative index for friction stresses existing in metalworking processes.

ISSN:0569-8197    

DOI:10.1080/05698197308982719

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The influence of some additives, mainly esters of aryl-phoshonic acids, on steel-steel friction in wide load and sliding speed ranges has been studied.

ISSN:0569-8197    

DOI:10.1080/05698197308982720

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A friction and wear life study was conducted on the use of a polyimide (PI) varnish as a binder for the solid lubricant, graphite fluoride (CF1.1)n. Also studied were the lubricating properties of PI thin films with no solid lubricant additives. For comparison, similar experiments on PI-bonded MoS2and burnished films of MoS2or (CF1.1)nwere conducted. The best results were obtained with the PI-bonded (CF1.1)nfilms. The polyimide thin films (with no solid lubricant additives) did not lubricate well at 25 C; however, when heated to 100 C, low friction and long wear lives were obtained.Presented as an American Society of Lubrication Engineers paper ot the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

ISSN:0569-8197    

DOI:10.1080/05698197308982721

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The friction coefficient of solid poly(n-alkyl methacrylates) decreases progressively with increasing length of the alkyl group. This behavior parallels the behavior of adsorbed films of these polymers from solution on solid surfaces. Durability of thin films of these polymers (approximately 3,500 Å thick) increases with increasing length of alkyl group. For example, when the alkyl is C22the durability is four times greater than when the alkyl is C12(polymer film on a 1020 steel substrate). The film durability is strongly substrate dependent, e.g., durability of poly(n-dodecyl methacrylale) is three times greater on glass than on 1020 steel when rubbed with a 440 C rider. The friction and durability are attributed to side chain crystallinity of the polymer. Side chain crystallinity has been observed by others using x-ray and other techniques when the alkyl group is at least 10 or 12 carbons long. Friction measurements may be a more sensitive way of detecting side chain crystallinity. The friction behavior of adsorbed films from solution of the poly(n-alkyl methacrylates) suggests that side chain crystallinity also pertains to suck adsorbed films.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

ISSN:0569-8197    

DOI:10.1080/05698197308982722

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

For seven bronzes of different composition and structure the ability to form boundary lubricant films is described in terms of a transition temperature at which the mild (abrasive) wear process changes into a severe (adhesive) one. Addition of lead or phosphorus to Cu 6Sn lowers this transition temperature considerably. Probably the formation in the bronze of finely dispersed tin-oxide particles is beneficial, surplus phosphorus inhibiting the formation of such particles. Oxidationin situdoes not improve the adsorption properties of the surface. Effective boundary films are formed on a thin transferred bronze film on the shaft, rather than on the bearing surface itself.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

ISSN:0569-8197    

DOI:10.1080/05698197308982723

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Friction-speed characteristics of full journal bearings made from Cu6Sn10Pb and Cu6Sn with and without phosphorus were determined, using a straight mineral white oil as lubricant. It was found that the bearings run in smoothly if the bearing-operating temperature remains below Tt, i.e., the transition temperature for effective boundary lubrication. At bearing-operating temperatures above Tt, boundary lubrication fails, and wear and surface deterioration interfere with the formation of a hydrodynamic lubricant film, a consequence being that phosphorus-free alloys behave better than phosphorus-containing alloys. This effect was also found with a crankcase oil of HD SAE 20W type.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

ISSN:0569-8197    

DOI:10.1080/05698197308982724

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A test rig has been developed to study relative radiation stability of lubricating oils of various chemical composition under dynamic test conditions. This apparatus allows the variations in torque to be recorded during the test.

ISSN:0569-8197    

DOI:10.1080/05698197308982725

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Low contact resistance between metal surfaces is often observed in spite of interposed lubricant and/or oxide films. To study this effect an apparatus is used with which normal force and tangential microdisplacement are applied between a small lead rider and a gold flat with various surface film conditions. Simultaneous oscillograph records are made of forces, displacement, and contact resistance. A unique low compliance force transducer allows direct recording of the frictional behavior during microdisplacement.

ISSN:0569-8197    

DOI:10.1080/05698197308982726

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor