Load-Carrying Properties of Metal Dialkyl Dithiophosphates: Application of Electron Probe Microanalysis

1968 ◽  
Vol 183 (16) ◽  
pp. 35-49
Author(s):  
E. S. Forbes ◽  
K. G. Allum ◽  
H. B. Silver
Keyword(s):  
Surface Layer ◽  
Surface Topography ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Mixed Lubrication ◽  
Wear Scar ◽  
Element Content ◽  
Extreme Pressure ◽  
Load Carrying ◽  
Dialkyl Dithiophosphates

The surface topography and the nature of the surface layer of wear scars obtained with Bi(III), Pb(II), Cd(II), Ni(ll), and Zn(II) di-(4-methylpentyl-2) dithiophosphates, using the four-ball machine, have been studied using an electron probe microanalysis (EPMA) technique. The results show that the nature of the dithiophosphate markedly affects the surface topography, element content, and distribution of the wear scar in both the extreme pressure and mixed lubrication or antiwear regions. The implication of these EPMA results on the load-carrying mechanism of metal dialkyl dithiophosphates is discussed.

The Load-Carrying Properties of Metal Dialkyl Dithiophosphates: The Effect of Chemical Structure

1968 ◽  
Vol 183 (16) ◽  
pp. 7-14 ◽  
Author(s):  
K. G. Allum ◽  
E. S. Forbes
Keyword(s):  
Metal Atom ◽  
Alkyl Group ◽  
Chemical Structure ◽  
Mixed Lubrication ◽  
Extreme Pressure ◽  
Load Carrying ◽  
Dialkyl Dithiophosphates

The extreme pressure (e.p.) and mixed lubrication or antiwear (a.w.) properties of a range of metal dialkyl dithiophosphates have been examined using the four ball machine. The results show that the nature of the metal atom is a major factor in determining these properties, and that the factors governing e.p. and a.w. activities are different. Thus the order of decreasing e.p. activity is Bi(III) > Ag(I), Pb(II) > Sb(III), Sn(II) ≥ Cd(II), Fe(III), Ni(II) > Zn(II), whilst the order of decreasing a.w. activity is Cd(II), Zn(II), Ni(II) ≥ Fe(III) > Ag(I) > Pb(II) > Sb(III), Sn(II) > Bi(III) for a series of 4-methylpentyl-2 and n-hexyl salts. The nature of the alkyl group has a lesser effect on either e.p. or a.w. properties. Possible explanations for these results are presented.

Antiwear and extreme pressure performance of castor oil with nano-additives

2017 ◽  
Vol 232 (9) ◽  
pp. 1055-1067 ◽  
Author(s):  
Rajeev Nayan Gupta ◽  
AP Harsha
Keyword(s):  
Castor Oil ◽  
Sodium Dodecyl ◽  
Wear Scar ◽  
Suspension Stability ◽  
Additive Concentration ◽  
Extreme Pressure ◽  
Wear Scar Diameter ◽  
Load Carrying ◽  
Nano Additives ◽  
Analytical Tools

The aim of the present study is to examine the antiwear, antifriction, and extreme pressure performance of castor oil with nano-additives by using a four-ball tester. CeO2 (≈90 nm) and polytetrafluroethylene (≈150 nm) nanoparticles were used as an additive in castor oil with four different concentrations in the range of 0.1–1.0% w/v. The suspension stability of the nanoparticles was improved by using sodium dodecyl sulfate as a dispersant. Different analytical tools were used to characterize the nanoparticles parameter (i.e. shape and size) as well as the worn surfaces. The additive concentration was optimized on the basis of tribological performance. The test results of antiwear and extreme pressure property have been reported on the basis of wear scar diameter and weld load, respectively. For the antiwear test, it was observed that the maximum reduction in the wear scar diameter was 37.4 and 35.3% at an optimum concentration of CeO2 and polytetrafluroethylene additive, respectively. Also, antifriction and load carrying properties of castor oil were significantly improved with the addition of nanoparticles as an additive in a small amount. The mechanism for such improvement in the tribological behavior has also been discussed.

scholarly journals Performance of Additives Concerning Synergistic Effect in Lube Oil

2020 ◽  
Vol 9 (3) ◽  
pp. 1874-1878 ◽  
Keyword(s):  
Synergistic Effect ◽  
Wear Scar ◽  
Load Carrying Capacity ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Wear Scar Diameter ◽  
Lubricating Oils ◽  
Effect Of Additives ◽  
Reducing Ability ◽  
Load Carrying

Lubricating oils containing ester, gaining more importance due to their friction reducing ability. Screening the performance of lubricating oils prior to field test is of most significance for the new lubricant formulations. In this endeavor, six lubricating blends were formulated having variable concentration of additives (sulfur and ester) in mineral oil and screened for their performance using four-ball tribo-tester. The formulated blends were evaluated for their extreme pressure and anti-wear characteristics as per ASTM standards. Tests were conducted on DUCOM TR- 30L four-ball tester and wear scar diameter were measured on an optical microscope.Compatibility and synergy of additives have been discussed on the basis of various parameters such as anti-wear scar diameter, mean scar diameter (just below weld load), mean scar diameter (at last non-seizure load), weld load and load wear index. The findings of this study demonstrate that ester along-with sulfur not only boost anti-wear properties but also enhance load carrying capacity of oil. An addition of sulfur beyond 2 % may not yield any significant improvement of tribo-characteristics of these oils.This paper is highlighting the synergistic effect of additives to render it as suitable lubricant for metal working applications. This paper also suggested an optimum concentration of an additive for its suitability for anti-wear and/(or) extreme-pressure properties.

Electron Probe Microanalysis of Frozen Hydrated Kidneys, Isolated Cells, and Cultured Cells

1982 ◽  
Vol 40 ◽  
pp. 402-403 ◽  
Author(s):  
Claude Lechene
Keyword(s):  
Liquid Nitrogen ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Cultured Cells ◽  
Liquid Nitrogen Temperature ◽  
Elemental Content ◽  
Isolated Cells ◽  
Renal Tubular Cells ◽  
Diamond Saw ◽  
Saw Blade

Electron probe microanalysis of frozen hydrated kidneysThe goal of the method is to measure on the same preparation the chemical elemental content of the renal luminal tubular fluid and of the surrounding renal tubular cells. The following method has been developed. Rat kidneys are quenched in solid nitrogen. They are trimmed under liquid nitrogen and mounted in a copper holder using a conductive medium. Under liquid nitrogen, a flat surface is exposed by sawing with a diamond saw blade at constant speed and constant pressure using a custom-built cryosaw. Transfer into the electron probe column (Cameca, MBX) is made using a simple transfer device maintaining the sample under liquid nitrogen in an interlock chamber mounted on the electron probe column. After the liquid nitrogen is evaporated by creating a vacuum, the sample is pushed into the special stage of the instrument. The sample is maintained at close to liquid nitrogen temperature by circulation of liquid nitrogen in the special stage.

Analysis of completed commercial semiconductors using EPMA

1996 ◽  
Vol 54 ◽  
pp. 502-503
Author(s):  
R. Packwood ◽  
M.W. Phaneuf ◽  
V. Weatherall ◽  
I. Bassignana
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Semiconductor Industry ◽  
Detection Limits ◽  
High Technology ◽  
Depth Resolution ◽  
Analytical Instruments ◽  
Wide Range ◽  
Numerous Element ◽  
Choice Method

The development of specialized analytical instruments such as the SIMS, XPS, ISS etc., all with truly incredible abilities in certain areas, has given rise to the notion that electron probe microanalysis (EPMA) is an old fashioned and rather inadequate technique, and one that is of little or no use in such high technology fields as the semiconductor industry. Whilst it is true that the microprobe does not possess parts-per-billion sensitivity (ppb) or monolayer depth resolution it is also true that many times these extremes of performance are not essential and that a few tens of parts-per-million (ppm) and a few tens of nanometers depth resolution is all that is required. In fact, the microprobe may well be the second choice method for a wide range of analytical problems and even the method of choice for a few.The literature is replete with remarks that suggest the writer is confusing an SEM-EDXS combination with an instrument such as the Cameca SX-50. Even where this confusion does not exist, the literature discusses microprobe detection limits that are seldom stated to be as low as 100 ppm, whereas there are numerous element combinations for which 10-20 ppm is routinely attainable.

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