On 11th of September Prof. Kalin was presented on the national radio RTV SLO 1 in the ARS show, which in a popular portrait interview presents reputable Slovenian intellectuals and researchers. In this interview, Prof. Dr. Kalin is presenting his work and the work of TINT laboratory in the field of investigation of lubrication, mechanisms of friction and wear as well as of research on nonconventional materials. The interview is available on the RTV SLO webpage: http://4d.rtvslo.si/arhiv/podobe-znanja/174359485
F.35 Other
COBISS.SI-ID: 14379035Recently TINT group and Prof. Kalin have performed some researches, which present novelties in the field of tribology, boundary and hydrodynamic lubrication. Results of these researches were published in eminent journals and were presented as invited lectures at several international conferences. Researches are in particularly focused on surface tension, surface energy and consequently wetting, and how all these properties influence interactions in different lubrication conditions. The question that also arise is how we can by above mentioned concepts achieve environmentally acceptable “green” technologies of lubrication. In the interview, prof. Kalin has explained the content and the relevance of all these researches. He also highlighted the background and all the issues concerning these researches.
F.35 Other
COBISS.SI-ID: 14377499DLC coatings continue to grow their use and importance in many industrial applications. From their early anti-sticking and low friction role in dry conditions, their role and benefits in lubricated contacts are more and more important. A special issue became the low SAPS additives and other green lubrication concepts due to environmental effects and legislation behind this. A combination of DLC with inherently low wear and low friction behavior offers a potential to use milder and greener additives. However, adsorption of any additive, even mild, must be well controlled and understood, which is still not resolved completely. Moreover, in recent studies it was revealed that DLC coatings offers also a low friction in EHD lubrication. The low friction was strongly correlated with surface energy of DLC and their wetting behavior, which also have an influence on adsorption of oils and additives. These phenomena and some early results from various experimental methods and techniques are discussed in this work.
B.04 Guest lecture
COBISS.SI-ID: 14210075In the PhD thesis we have studied the effect of slip between a surface and a lubricant on the friction in lubricated engineering macro-contacts. First, we have introduced a theoretical background of the discussed phenomena and provided an overview of up-to-date research in this field, which demonstrates that current understanding of the slip of lubricating oils over engineering surfaces is still poor, also due to the lack of the understanding of the role of wetting in this process. In the results section of the PhD thesis we have thus presented interlinked connections of the surface properties of engineering surfaces and lubricants with wetting. In this respect we have shown that for the evaluation of wetting of engineering surfaces with lubricating oils a spreading parameter needs to be used instead of contact angle. The spreading parameter is also a key tool for controlling the slip and consequently the friction in lubricated contacts. Furthermore, based on the finding that the type of the intermolecular interactions significantly affects the wetting, we have proposed a tentative slip model, which explains that the lack of the permanent polar interactions between the lubricant and the surface increases the slip. Subsequently, we have presented an iterative procedure for the evaluation of slip in macro-contacts by introducing a novel virtual slip parameter. With such procedure and parameter we have clearly revealed the limitations of the most commonly used slip length parameter for the optimization of friction properties in lubricated contacts, which is based on its dependence of the lubricating film thickness. Finally, we have also demonstrated how slip and friction can be affected by changing the surfaces of the contact and the contact kinematics. In this respect we can under certain conditions obtain similar friction-decreasing effects as in the contacts with the slip on the both contact surfaces also in the contacts with only one slipping surface which presents an important technological contribution.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 14406939Extensive research has been carried out to investigate the effects of different additives on wear, friction and boundary film formation in DLC contacts, which is still of great interest since it is broadly unknown. As reduction of harmful elements in lubricants is an important issue, this study investigates the reactivity of various low SAPS and high SAPS lubricants when lubricating different DLC coatings. Primarily, a correlation between nano scale boundary film properties and macroscopic friction behaviour of DLC is studied. Atomic force microscope in various modes was used as the main tool for investigation of surfaces and tribofilms. These results should provide us with important fundamental understanding of tribofilm importance in boundary lubrication of various DLC contacts.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 14002203