Unusual tribochemical polishing
A DFG-funded project with collaborators from the Fraunhofer Institute for Mechanics of Materials (IWM) and the Freiburger Materialforschungszentrum (FMF) has revealed a rather special case of tribochemical polishing which leads to a ultralow coefficient of friction between two steel surfaces.
If certain 1,3-diketones are brought between two steel surfaces rubbing against each other a very low friction coefficient is found after a short running-in period. It is suggested that the extremely favorable friction properties are caused by a tribochemical reaction between the 1,3-diketones and the steel surfaces, leading to formation of a chelated iron–diketo complex. With progression of the tribochemical reaction, the sliding surfaces become very conformal and smooth, so that the pressure is greatly reduced and further wear is strongly reduced. All iron particles potentially generated by wear during the initial running-in period are completely dissolved through complex formation. It is proposed that the tribochemical polishing reaction causes a transition from boundary lubrication to fluid lubrication.
These findings and some theoretical aspects of the complex formation were now published in two papers which recently appeared in Langmuir (DOI: 10.1021/la400333d) and in the Journal of Physical Chemistry A (DOI: 10.1021/jp400980y).
Azubi gesucht