Ultrathin boundary lubricant films

This section addresses the question, how does one measure the minimum lubricant film thickness in boundary lubrication  

In siri4 /Tojr mortem H y brid i 2 ation/phases XAS/CEIVIS  

In itu fyr xt mortem Phasc/local structure XEM/EELS EXELFS  

This section addresses the questions, what kind of physicochemical interactions occur between antiwear additives and the contacting surfaces, and how do they depend on the nature of the environment during friction  

The role of antiwear additives in boundary lubrication has been mentioned briefly in the general presentation (Section 1). The way in which zinc dithio-phosphate (ZDDP) acts as an antiwear additive is almost certainly that of the elimination of the abrasive wear contribution of crystallized iron oxide species as a result of their tribochemical reactions with the additive molecules and/or various degradation products. The use of XAS and TEM/EELS together with complementary CEMS and AES represents a powerful analytical combination for the elucidation of the tribochemical reactions responsible for antiwear mechanisms. The first part of this section summarizes analytical results obtained with friction tests carried out in the ambient atmosphere. The second part describes some original results obtained with friction tests and in situ post mortem AES analysis in ultrahigh vacuum. In this way the intrinsic frictional properties of the solid reaction film itself, without the effect of the environment, and the ability of friction to modify the nature and the structure of the surface films are investigated. 

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Recently, ultrathin organic thin films attract attention as new film lubricant [51]. Organosilane monolayer, which is one of the ultrathin films, has been identified as promising boundary lubricants. This is because organosilane molecules interact strongly with substrates and they are robust against solvent and temperature increase. Friction and wear tests of monolayers were carried out with a conventional ball-on-disk type friction tester (SHINTO Scientific Co. Ltd.) in air and tetradecane at 298 K. A 5.0 mm radius ball made of stainless steel was slid on a disk. The friction coefficient was determined by the distortion of a... 

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