Chia-Jui Hsu, Jenifer Barrirero, Rolf Merz, Andreas Stratmann, Hisham Aboulfadl, Georg Jacobs, Michael Kopnarski, Frank Mücklich and Carsten Gachot
To decrease wear and friction, zinc dialkyldithiophosphate (ZDDP) has been used in engine oil for several decades, but the mechanism of the tribofilm formation is still unclear…
Abstract
Purpose
To decrease wear and friction, zinc dialkyldithiophosphate (ZDDP) has been used in engine oil for several decades, but the mechanism of the tribofilm formation is still unclear. The purpose of this study is to characterize the chemical details of the tribofilm by using high-resolution approaching.
Design/methodology/approach
An ISO VG 100 mineral oil mixed with ZDDP was used in sliding tests on cylindrical roller bearings. Tribofilm formation was observed after 2 h of the sliding test. X-ray photoelectron spectroscopy (XPS) and atom probe tomography (APT) were used for chemical analysis of the tribofilm.
Findings
The results show that the ZDDP tribofilm consists of the common ZDDP elements along with iron oxides. A considerable amount of zinc and a small amount of sulfur were observed. In particular, an oxide interlayer with sulfur enrichment was revealed by APT between the tribofilm and the steel substrate. The depth profile of the chemical composition was obtained, and a tribofilm of approximately 40 nm thickness was identified by XPS.
Originality/value
A sulfur enrichment at the interface is observed by APT, which is beneath an oxygen enrichment. The clear evidence of the S interlayer confirms the hard and soft acids and bases principle.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/
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Keywords
Andreas Ziegltrum, Stefan Emrich, Thomas Lohner, Klaus Michaelis, Alexander Brodyanski, Rolf Merz, Michael Kopnarski, Bernd-Robert Hoehn and Karsten Stahl
This paper aims to address the influence of tribofilms and running-in on failures and friction of gears. The operation regime of gears is increasingly shifted to mixed and…
Abstract
Purpose
This paper aims to address the influence of tribofilms and running-in on failures and friction of gears. The operation regime of gears is increasingly shifted to mixed and boundary lubrication, where high local pressures and temperatures occur at solid interactions in the gear contact. This results in strong tribofilm formation due to interactions of lubricant and its additives with the gear flanks and is related to changes of surface topography especially pronounced during running-in.
Design/methodology/approach
Experiments at a twin-disk and gear test rig were combined with chemical, structural and mechanical tribofilm characterization by surface analysis. Pitting lifetime, scuffing load carrying capacity and friction of ground spur gears were investigated for a mineral oil with different additives.
Findings
Experimental investigations showed a superordinate influence of tribofilms over surface roughness changes on damage and friction behavior of gears. Surface analysis of tribofilms provides explanatory approaches for friction behavior and load carrying capacity. A recommendation for the running-in of spur gears was derived.
Originality/value
Experimental methods and modern surface analysis were combined to study the influence of running-in and tribofilms on different failures and friction of spur gears.
Details
Keywords
There has been growing convergence between EU member states over the perceived China threat, especially related to economic matters. However, at the same time, EU countries are…
Details
DOI: 10.1108/OXAN-DB272249
ISSN: 2633-304X
Keywords
Geographic
Topical
The purpose of this paper is to show how industrial ecology can facilitate the achievement of sustainable development through its incorporation into an engineering curriculum.
Abstract
Purpose
The purpose of this paper is to show how industrial ecology can facilitate the achievement of sustainable development through its incorporation into an engineering curriculum.
Design/methodology/approach
A model has been developed for assessing sustainability learning outcomes due to the incorporation of the concept of industrial ecology into undergraduate and postgraduate engineering programs. This model assesses how the Engineering Faculty at Curtin University has included a core engineering unit (Engineering for Sustainable Development) and four postgraduate units (Cleaner Production Tools, Eco‐efficiency, Industrial Ecology and Sustainable Technology) in its undergraduate and postgraduate engineering program, to enable modern engineering education to reflect the benefits of industrial ecology in the implementation of sustainable engineering solutions and decision‐making processes. Using this model, this paper demonstrates how the syllabus, interdisciplinary and multidisciplinary assignment tasks, lectures and tutorials have been developed since 2006 in order to develop the concept of industrial ecology in undergraduate and postgraduate engineering education. The paper has also analysed the different teaching methods that have been applied since 2006 to generate increased student satisfaction in these new and challenging subjects.
Findings
The university environment can temper the potential outcomes from increasing the sustainability content in engineering education, given the general lack of student maturity in understanding the value of sustainability objectives together with course limitations on sustainability content and the arduous and lengthy processes involved in changing course curricula.
Research limitations/implications
Since the Engineering for Sustainable Development unit has been introduced only recently, it was beyond the scope of the research to interview graduate engineers who completed this unit to investigate how they have applied the concept of industrial ecology to achieve sustainability outcomes in their workplaces.
Originality/value
This research is distinct in that it investigated the implications of the incorporation of industrial ecology into the engineering curriculum.