摘要:

AbstractThis paper is concerned with the effects of the colloidal aspect in boundary lubrication. The newly developed method for surface forces measurement has clearly shown the consolidation effect during contact loading.The paper also shows that, in some cases, the friction coefficient varies with the compaction of wear particles in the contact. Friction experiments between a ball and flat (both sapphire) in which the contact is immersed in water, have been performed to understand the effect of compaction of worn material on friction. During friction, wear debris is piled up in the contact and shear behaviour depends on pressure and volume fraction of wear particles.

ISSN:0954-0075    

DOI:10.1002/ls.3010050102

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe mechanism of overbasing of additives used in lubricating oils is studied. Overbased calcium sulphonates, the most widely used, are examined. Although the geometrical and physical nature of colloidal carbonate particles has been well studied, little is known about the fundamental aspects and mechanism of the overbasing process. In this paper, assessment of the physical and/or chemical nature of the reaction is made from equations related to the chemical engineering model of the shrinking spherical particle. The results show that the overbasing process is under diffusion control, and the chemical reaction is not determining.

ISSN:0954-0075    

DOI:10.1002/ls.3010050103

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractLaser microprecision treatment of the surfaces of mechanical parts takes place after machining, where the surfaces of mechanical parts, especially highly‐loaded (counterformal) parts (e.g. gears, rolling bearing and cams with point or line contact) are re‐treated microprecisely by laser to produce an asperity texture with transverse orientation. This man‐made surface topography is favourable to EHD lubrication of parts in relative motion and greatly increases the load capacity of such parts. Timken tests of rings whose surfaces were treated microprecisely by laser demonstrate its ability to raise the Timken OK loads (or anti‐scuffing ca

ISSN:0954-0075    

DOI:10.1002/ls.3010050104

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA technique known as the Carbonyl Peak Index (CPI) is used to assess the relative oxidation stabilities of two competing grades of commercial automotive crankcase oils, their base oils, and the oxidation characteristics resulting from oil/metal interactions. The CPI provided empirical data from the infrared spectra which enabled a more lucid explanation of the oil soluble acidity and sludge deposition characteristics of the oils. A combination of these parameters has confirmed that the hydrocarbon type composition of the oils gave some stability to the fully formulated monograde oil. Consequently, the monograde base oil was found to possess a greater stability towards oxidation than the multigrade base oil under the conditions of test. However, the fully formulated oils were found to be more stable than the base oils, mainly due to the added antioxidants. Metals in the oils acted as antioxidants initially, but later turned to pro‐oxidants. The reversal of metal action from inhibition to autooxidative catalysis was also found to be base‐oil hydrocarbon‐type dependent and this has been related to the natural antioxidant capacity of the

ISSN:0954-0075    

DOI:10.1002/ls.3010050105

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA mixed model to predict friction forces in thermohydrodynamic lubricated contacts with non‐Newtonian fluids is proposed, with an integral formulation and a finite element method resolution. The mixed model is used here for the first time in lubrication. It takes into account the implicit rheological laws. The shear stress field appears in this formulation as a nodal unknown and eases the use of rheological laws with yield criteri

ISSN:0954-0075    

DOI:10.1002/ls.3010050106

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010050101

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY