Ultrahigh vacuum ESR studies on clean metal surfaces: NO2 on copper

1980 ◽  
Vol 73 (1) ◽  
pp. 588-589 ◽  
Author(s):  
M. Nilges ◽  
M. Shiotani ◽  
C. T. Yu ◽  
G. Barkley ◽  
Y. Kera ◽  
...  
Keyword(s):  
Metal Surfaces ◽  
Ultrahigh Vacuum ◽  
Clean Metal

The development of wear-protective oxides and their influence on sliding friction

1980 ◽  
Vol 369 (1739) ◽  
pp. 557-574 ◽  
Keyword(s):  
Metal Oxide ◽  
Coefficient Of Friction ◽  
Metal Surfaces ◽  
Sliding Friction ◽  
Constant Thickness ◽  
Partial Pressures ◽  
Metal Wear ◽  
The Coefficient Of Friction ◽  
Metal Wear Particles ◽  
Clean Metal

The friction behaviour of iron and Fe-Cr alloys in unidirectional and reciprocating sliding motions at 293 K has been examined in oxygen of controlled partial pressure. During sliding, a progressive decrease in coefficient of friction accompanies the development of compacted oxide films on the metal surfaces, eventually resulting in a steady value of about 0.6 when almost complete oxide coverage is attained. This is achieved more rapidly at higher oxygen partial pressures. A model to account for the experimental observations is proposed, based on the growth of oxide on the clean metal surfaces and metal wear particles between each wear traversal and the removal of that oxide during the subsequent traversal. The oxidized debris is fragmented further and compacted on to the metal surfaces to form a layer of nominally constant thickness, the area of which increases progressively with the number of sliding traversals. The model relates the coefficient of friction to the area of compacted oxide in terms of several interfacial metal, oxide and metal-oxide parameters. The importance of some of these parameters on the frictional behaviour is discussed in light of the experimental observations.

Observation of Ps(n=2) from well-characterized metal surfaces in ultrahigh vacuum

1992 ◽  
Vol 45 (3) ◽  
pp. 1407-1411 ◽  
Author(s):  
D. C. Schoepf ◽  
S. Berko ◽  
K. F. Canter ◽  
P. Sferlazzo
Keyword(s):  
Metal Surfaces ◽  
Ultrahigh Vacuum

Relaxation at clean metal surfaces

1986 ◽  
Vol 59 (5) ◽  
pp. 275-280 ◽  
Author(s):  
P. Jiang ◽  
P.M. Marcus ◽  
F. Jona
Keyword(s):  
Metal Surfaces ◽  
Clean Metal

Collisions through liquid films

1948 ◽  
Vol 44 (4) ◽  
pp. 566-580 ◽  
Author(s):  
F. R. Eirich ◽  
D. Tabor
Keyword(s):  
Plastic Deformation ◽  
Liquid Film ◽  
Metal Surfaces ◽  
High Pressures ◽  
Early Experiment ◽  
Liquid Films ◽  
Metallic Contact ◽  
Dynamic Yield ◽  
Energy Dissipated ◽  
Clean Metal

When impact occurs between clean metal surfaces, plastic flow of the metal usually takes place at the points of real contact, so that the pressures developed are as high as the dynamic yield pressure of the metal concerned. Early experiment show that if the surfaces are covered with a thin film of a highly viscous liquid, the pressures developed and transmitted through the liquid film may be sufficiently great to produce plastic deformation of the metal, even though no metallic contact occurs through the film (1). The existence of these high pressures in the liquid layer means that extremely high rates of flow and shear may be developed in the liquid film, and that the energy dissipated in overcoming viscous flow may lead to an appreciable temperature rise in the liquid. Even in much gentler impacts, where plastic deformation of the metal surfaces does not occur, very high pressures, rates of flow and shear, etc., may be developed in the liquid film. These effects are of great interest in any study of collisions through liquids; they are of particular significance in the study of the mechanism of detonation of liquid explosives by impact.

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