摘要:

AbstractThis paper deals primarily with the potential extreme‐pressure (EP) activity of certain cyclic disulphide additives in paraffin oil. The antiwear and antifriction properties of 1,2,4‐dithiazo‐line additives have been evaluated on a four‐ball machine by using 12.7 mm diameter steel ball bearing specimen‐I. The paper also includes a discussion on the effectiveness of 3‐p‐Cl‐phe‐nylimino‐5‐(N‐methylphenyl)amino‐1,2,4‐dithiazoline on steel bearing balls of different compositions. The topography and the surface chemistry of the bearing ball wear scar were studied by Scanning Electron Microscopy (SEM) and Auger E

ISSN:0954-0075    

DOI:10.1002/ls.3010040402

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAluminium is situated beneath boron in the same group of the periodic table. As borate is a good antiwear agent for lubricating oils, it is possible that aluminium compounds maybe possess antiwear properties similar to borate. After testing seven alkoxy aluminium compounds, the results support this assumption. The most efficient compound is triethoxy aluminium. When 2% mass of triethoxy aluminium is added to ISO VG 68 oil, the load wear index of a four‐ball machine increases from 219 N to 519 N and the weld point from 1568 N to 4900 N. This compound also exhibits good corrosion protection property. In the present work, after steel balls of a four‐ball machine were run in aluminium‐containing oil, the wear scars were analysed by scanning electron microscope and X‐ray energy dispersion analysis. The main compositions discovered on the scar surface were 5.7–48.3 atom % of iron, 4.4–11.2 atom % of aluminium, 37.1–59.1 atom % of oxygen, 8.7–23.5 atom % of carbon, and 0.3–1.1 atom % of chromium, under 3087 N–39 200 N of axial loads. When the loads are lower than 2450 N, the contents of oxygen are almost equal to zero and the contents of iron increase to 68.6–93.8 atom %. Based on the results of surface analysis and using thermodynamic principles, an antiwear action mechanism for triethoxy aluminium is suggested: under low loads, the weaker bond C‐C (350 KJ /mol) is broken, and the broken fragments may form polymer film during friction processes. As the loads increase, the stronger bond Al‐O (484.5 KJ /mol) is broken to create active aluminium and oxygen. The oxygen reacts with aluminium and iron to form a complicated solid solution containing AlxOY, FExOy on the surface. This complicated surface layer raises the weld

ISSN:0954-0075    

DOI:10.1002/ls.3010040403

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe effect of surface roughness on lubrication of piston ring and cylinder is examined. In particular, the temperature effect is considered, and a model proposed to overcome shortcomings in the previous mathematical model. Further, film thickness was measured by transducer capacitance method in a S195 diesel engine. The results found are consistent with theoretical results. In addition, the authors show quantitatively the value of friction power losses of the ring package of a S195 diesel engine.

ISSN:0954-0075    

DOI:10.1002/ls.3010040404

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this paper we compare the action mechanisms of different ‘non‐soluble’ additives: a dispersion of potassium triborate and overbased detergents formed by calcium carbonate, or borate aggregates dispersed by a detergent. These additives act by producing a deposit issued from their mineral phase, on the friction surface. With the potassium triborate, a solid film of borate, bound to the metal, is only detected on a negatively‐polarised surface or in conditions of severe wear when friction surfaces have been activated by abrasion. On the contrary, with the overbased detergent, a solid film is always detected on the friction surfaces, even without activation by abrasion. This additive is decomposed in the contact zone by the effect of the elevated pressure. The present study shows that the method of placement in suspension of the inorganic phase by the detergents is important. It offers the advantage of forming deposits only in the friction zone, instantly and independently of the type and state of the friction

ISSN:0954-0075    

DOI:10.1002/ls.3010040405

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBackward extrusion of steel is a deformation process in which very high forces and tool pressures occur. Reduction of such high forces and tool pressures is possible by using an efficient lubricant. This paper describes an experimental investigation of the influence of different lubricants on the stress‐strain state within the workpiece volume as well as on the stressing of the die. Best results were obtained when a phosphate‐coated specimen was lubricated with M

ISSN:0954-0075    

DOI:10.1002/ls.3010040406

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010040407

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010040401

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY