摘要:

AbstractThis paper discusses the preparation of bismuth dialkyldithio‐phosphate as an oil‐soluble antiwear and extreme pressure additive for lubricants. Its tribological performance when added to an ISO VG32 mineral oil was evaluated on a four‐ball tester and a ring‐on‐block machine. The relationships between its performance and the concentrations are also given, and are compared with those of zinc dialkyldithiophosphate (ZDDP). The results show that the compound not only possesses good antiwear and friction‐reducing abilities, but also has a higher load‐carrying capacity than ZDDP. The mechanism of action of the additive was studied by surface analysis. A scanning Auger microprobe revealed a high bismuth content in the rubbing surface layers, and X‐ray photoelectron spectroscopy detected the formation of various chemical species including organic films, metallic bismuth, bismuth oxide, and bismuth sulphide. The mechanism of action is postulated on the basis o

ISSN:0954-0075    

DOI:10.1002/ls.3010110102

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractA complex of lanthanum and di‐(2‐ethyl hexyl) phosphate (DEHP) was prepared by an extractive method. The friction and wear behaviour of this complex (called LaDEHP) as an oil additive was evaluated using a four‐ball wear tester. For comparison, the friction reduction and antiwear properties of DEHP as an oil additive were also investigated. The chemical composition of the boundary film formed after wear tests was examined using X‐ray photoelectron spectrometry (XPS).Four‐ball tests showed that the prepared LaDEHP was effective in reducing friction and wear as well as in increasing load‐carrying capacity. XPS analyses indicate the formation of iron phosphate and lanthanum oxide in the bou

ISSN:0954-0075    

DOI:10.1002/ls.3010110103

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractIn this paper is discussed the effect of the physical characteristics of substrate surfaces on the lubrication properties of thin films at nanometre scale. Different coatings with different surface energies have been formed on the surface of a steel ball by means of plasma assisted sedimentation (PAS). The ball was put in a pure rolling system in point contact, where the lubricant film is measured by relative optical interference intensity (ROII). Experimental results show that the film thickness is closely related to the substrate surface energy when the film is in the nanometre scale, and that the combined surface roughness in the contact region is closely related to the liquid lubricant film thickness and the contact pressure. The thinner the film and the higher the contact pressure, the smaller will be the combined surface roughness. Lastly, the relationship between critical film thickness and its influencing factors is discussed.

ISSN:0954-0075    

DOI:10.1002/ls.3010110104

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractThe friction and wear properties of an Al‐Si alloy against AISI 52100 steel were investigated with a block‐on‐ring wear tester lubricated with a liquid paraffin base oil containing organic additive compounds, such as ethylenediamine, ethyleneglycol, ethanolamine, and N,N‐dibutylethanolamine. The boundary film formed on the rubbed surface of the Al‐Si alloy was then examined using FT‐IR microscopy and XPS.The friction and wear tests revealed that ethylenediamine, ethanolamine and N,N‐dibutylethanolamine additives provide good lubrication in the Al‐Si alloy‐on‐steel system, especially N,N‐dibutylethanolamine. FT‐IR microscopy and XPS revealed the possible formation of a chemically stable five‐ring complex of aluminium or silicon with

ISSN:0954-0075    

DOI:10.1002/ls.3010110105

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractA multistage mechanism of lubrication layer formation during cutting is described and the necessary conditions for the formation of a lubrication layer are formulated. It is considered that the process of physical adsorption of the tribo‐active components of the cutting fluid in the contact zone between tool and chip during metal cutting is one step in a multistage process which occurs in the interface capillary system. A mathematical model describing simultaneous diffusion and adsorption of tribo‐active components in a single interface capillary is proposed. Some parameters for a model determining the efficiency of the lubricating action of surface‐active additives are also pro

ISSN:0954-0075    

DOI:10.1002/ls.3010110106

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractIn trying to understand the behaviour of solutions of polymer in mineral oils, a styrene‐isoprene copolymer and two mineral oils have been studied. The base oils showed Newtonian behaviour, and the polymer solution non‐Newtonian behaviour, in the temperature range 50–100°C. The variation of viscosity with shear rate can be approximated to a power law model within the same temperature range and 0–104s−1shear rate. The free energy of activation is used to explain the flow behaviour qua

ISSN:0954-0075    

DOI:10.1002/ls.3010110107

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractIn the present work, variation in the resistivity of different greases with time in static conditions, under the influence of applied potential drops, is established. The change in resistivity and physico‐chemical characteristics of the greases in electric fields, and recovery of the resistivity within the test period in the absence of applied potential drop, have been found.The properties of the greases are compared, and their correlation with resistivity is analysed.The paper also gives the results of analysis using an SRV tester, IR spectra, chemical analysis and spectrophotometry, of changes that occurred periodically in the greases, normally used in non‐insulated rolling‐element bearings in the presence of a potential drop across the inner and outer races. The paper highlights the behaviour and mechanism of the process of bearing failure under electric f

ISSN:0954-0075    

DOI:10.1002/ls.3010110108

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010110101

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY