scholarly journals The role of soot particles in the tribological behavior of engine lubricating oils

Wear ◽  
2013 ◽  
Vol 304 (1-2) ◽  
pp. 152-161 ◽  
Author(s):  
Enzhu Hu ◽  
Xianguo Hu ◽  
Tianxia Liu ◽  
Ling Fang ◽  
Karl D. Dearn ◽  
...  
2019 ◽  
Vol 72 (3) ◽  
pp. 291-297
Author(s):  
Jibin T. Philip ◽  
Deepak Kumar ◽  
S.N. Joshi ◽  
Jose Mathew ◽  
Basil Kuriachen

Purpose Electrical discharge machining (EDM) is well-known for its credibility in the processing of advanced materials, which are electrically conductive. The strenuous effort associated with machining of Ti6Al4V (Ti64) using conventional methods, and its low tribological behavior, present an immediate need to develop solutions to monitor and improve the compatible techniques such as EDM. Design/methodology/approach The present work includes following: monitoring the ED process parameters, namely, current (I) and pulse on time (Ton), in controlling the material removal rate and surface roughness (Ra and Sa) for development of tribo-adaptive surfaces; and investigation on the role of oxides pertinent to the tribo-behavior of Ti64 (bare and EDMed) surfaces. Findings The tribological behavior of Ti6Al4V surfaces got remarkably improved through ED machining, which points to the credibility of the process to establish itself as a surface alloying technique. The recast layer (RL, alloyed matrix) acted as a protective coating; stable enough to assist the developed tribo-oxides such as TiO and Ti8O15 in rendering improved sliding performance at load = 50 N and speed = 0.838 ms−1. Originality/value The surface modification through ED machining was experimentally proven to improve the wear behavior of Ti6Al4V surfaces.


2005 ◽  
Vol 1 (4) ◽  
pp. 277-287 ◽  
Author(s):  
B. Collignon ◽  
P.N.M. Hoang ◽  
S. Picaud ◽  
J.C. Rayez

Clustering of water molecules on model soot particles is studied by means of quantum calculations based on the ONIOM approach. The soot particles are modeled by anchoring OH or COOH groups on the face side or on the edges of a graphite crystallite of nanometer size. The quantum calculations aim at characterizing the adsorption properties (structure and adsorption energy) of small water aggregates containing up to 5 water molecules, in order to better understand at a molecular level the role of these OH and COOH groups on the behavior with respect to water adsorption of graphite surface modelling soot emitted by aircraft.


2010 ◽  
Vol 204 (21-22) ◽  
pp. 3451-3458 ◽  
Author(s):  
A.P. Carapeto ◽  
A.P. Serro ◽  
B.M.F. Nunes ◽  
M.C.L. Martins ◽  
S. Todorovic ◽  
...  

Author(s):  
Alexandra Souchet ◽  
Julien Fontaine ◽  
Jean-Luc Loubet ◽  
Hassan Zahouani ◽  
Michel Belin ◽  
...  

The Ti3SiC2 compound is a thermodynamically stable nano-layered ternary carbide, that belongs to a family of over 50 ternary carbides and nitrides, so-called MAX phases. These phases are a new class of solids that possess a unique combination of properties: they are readily machinable, relatively soft for ceramics, but elastically stiff, and electrically and thermally conductive. However, only very few studies are dedicated to their tribological behavior. This paper presents some results on the tribological behavior of Ti3SiC2. During dry sliding on a Ti3SiC2 plane, a first regime of low friction and mild wear can be observed, with the build-up of a tribofilm on the counterface. Then, while in an apparently steady state, the tribological behavior suddenly turns to higher friction and severe wear of both counterfaces. Combining friction experiments and topographical observations of contacting surfaces during the first regime, we propose some explanations for such drastic transition in tribological behavior. While tribofilm thickness and roughness stabilize in the mild wear regime, the covering of the ball surface still increases. Thus, matter accumulation on the ball finally leads to seizure of the contact.


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