Bonus Content for STLE Members
Tribology and lubrication research
By Nicole Gleeson, Editorial Coordinator | TLT 20 Minutes July 2025
Explore excellence in tribology and lubrication research with these award-winning papers from Tribology Transactions journal.
Each year at the annual meeting, STLE recognizes a select group of individuals for their outstanding technical achievements in the field of tribology and lubrication through its publishing awards. All publishing awards are for papers appearing in Tribology Transactions, STLE’s bi-monthly scientific journal that contains peer-reviewed experimental and theoretical technical papers on lubrication, friction and wear of materials from the macro- to the nano-scale. Tribology Transactions features more than 2,000 published papers of relevance to a wide variety of industries and is read and referenced by thought-leaders in the field of tribology in countries around the world.
STLE members have full online access to Tribology Transactions and can search the complete archives of thousands of technical articles. Be sure to take full advantage of your STLE member benefits by keeping up with the latest tribology and lubrication research. Click here to explore more about Tribology Transactions, including member access, manuscript submission information and a list of editors.
The following papers were recognized at the 2025 STLE Annual Meeting for their excellence as the most outstanding research in the journal.
Edmond E. Bisson Award
The Bisson Award was named in honor of Edmond E. Bisson, a former STLE editor-in-chief who was instrumental in establishing the society’s reputation as a technical publisher. Established in 1991, the award is given to STLE members or non-members for the best written contribution published by the society in the year preceding the Annual Meeting. The contribution must deal with tribology, lubrication engineering or allied disciplines.
The winner of the Edmond E. Bisson Award is Breakdown voltages in thrust bearings: Behavior and Measurement by Simon Graf, Michel Werner, Oliver Koch, Stefan Götz and Bernd Sauer, all of University of Kaiserslautern-Landau (RPTU).
Abstract
This paper investigates breakdown characteristics in the bearings of variable speed electric drive trains. The analyses reveal that breakdown phenomena previously known from high-voltage technology appear to also occur in the bearing contact, though at significantly lower voltages. By loading the bearing with AC voltage of different frequencies at various mechanical load points, five states, which range from partial discharge through arc discharge to a completely conductive channel, emerge. Consistent with the concept that the magnitude of the breakdown voltage depends on the lubricant film height, the contact force and the frequency of the AC voltage, a thicker lubricant film results in a higher breakdown voltage, analogously to a capacitor with a larger plate spacing, which requires a higher potential difference to be punctured. Furthermore, the sinusoidal frequency of the AC load correlates with the breakdown voltage. The breakdown tends to occur earlier at low frequencies, which is illustrated by the fact that at low frequencies, capacitive behavior can only be observed at higher speeds, i.e., at a larger lubrication gap, while no voltage can be built up over the bearing at lower speeds. An increase of the contact force for the same lubricant film height lowers the breakdown voltages. The reduction of the breakdown voltage by the contact force may result from an increase of the relative permittivity of the lubricant with higher pressure and likewise of the contact area; the increased area may also increase the number of surface-roughness peaks where an increase in the electric field occurs.
Walter D. Hodson Award
The Hodson Award was established in 1950 and is given to the lead author of the best paper written by an STLE member 35 years of age or younger and published by the society in the year preceding the Annual Meeting. The purpose of the award is to stimulate the interest of young engineers in the science of tribology and lubrication and the activities of STLE.
The winner of the Walter D. Hodson Award is In Situ Visualization and Analysis of Oil Starvation in Ball Bearing Cages by Ujjawal Arya, Farshid Sadeghi and Saeed Aamer of Purdue University and Andreas Meinel and Hannes Grillenberger of Schaeffler Technologies AG & Co. KG.
Abstract
This article presents an investigation into oil starvation in different cage pocket shapes of a horizontally mounted ball bearing. A counter-rotating angular contact ball bearing test rig (CRACTR) was used to visualize the oil distribution inside specially manufactured transparent bearing cages using detailed images from a high-speed camera. Three different cage types were investigated using various oils dyed with ultraviolet dye. The identification of oil and air regions elucidated the oil distribution in the cage pocket and the formation of oil–air striations on the ball surface under various operating conditions. The experimental results demonstrated that raceway motion, ball submersion level, oil properties and cage pocket shape influenced oil starvation inside the bearing cage. ANSYS Fluent software was also used to develop an equivalent two-phase computational fluid dynamics (CFD) model for the test bearing. Results from the CFD model corroborate well with the experimentally observed oil distribution for all test cages and establish the strong influence of cage geometry on oil starvation and bearing lubrication.
Wilbur Deutsch Memorial Award
The Deutsch Award is named for a former STLE president and recognizes the most outstanding technical paper written on the practical aspects of lubrication published by the society in the year preceding the Annual Meeting.
The winner of the Wilbur Deutsch Memorial Award is Investigation of the Influence of Triboactive CrAlMoN Coating on the Joint Wear of Grease-Lubricated Roller Chains by Martin Rank, Manuel Oehler and Oliver Koch of University of Kaiserslautern-Landau (RPTU) and Kirsten Bobzin, Christian Kalscheuer and Max P. Möbius of RWTH Aachen University.
Abstract
Physical vapor deposition (PVD) coatings are vital for enhancing wear resistance. However, this technology faces challenges when coating inaccessible surfaces due to its line-of-sight characteristic. A potential remedy is utilizing triboactive CrAlMoN coatings. These form a tribofilm in the contact zone when applied to one contact partner along with a suitable lubricant. This tribofilm can subsequently safeguard inaccessible yet tribologically stressed surfaces. One of the main applications for this method is roller chain drives, whose longevity depends on the joint wear and the resulting chain elongation. Large-scale pin coatings have proven effective in curbing wear and prolonging chain life. However, the inaccessibility of bushes complicates standard PVD coating procedures. Triboactive coatings offer the possibility of forming transfer layers on the bushes, thereby enhancing friction reduction and wear protection. Experimental material studies for chain drives can be cost-intensive due to complexity and numerous components. This article demonstrates that CrAlN and CrAlMoN coatings in combination with greases with the additives phosphorus and sulfur can reduce friction and wear in chain joints. Furthermore, it is shown that a reasonable selection of tribometer testing can significantly reduce costs. Comparing the results of tests on a pin-on-disk tribometer and component tests show that model tests cannot completely replace component tests. But the combination offers an efficient way to optimize test matrices. Triboactive coatings like CrAlMoN hold promise for addressing the challenge of inaccessible surfaces. Reasonable tribometer test selection can help mitigate the costs of experimental studies, making these coatings a more practical solution.
Captain Alfred E. Hunt Award
Named for ALCOA’s first president, this award is given annually to the STLE member or members authoring the best technical paper dealing with the field of lubrication or an allied field.
The winner of the Captain Alfred E. Hunt Award is Load-Independent Power Losses of Fully Flooded Lubricated Tapered Roller Bearings: Numerical and Experimental Investigation of the Effect of Operating Temperature and Housing Wall Distances by Lorenzo Maccioni and Franco Concli of Free University of Bozen-Bolzano and Lukas Rüth, and Oliver Koch of University of Kaiserslautern-Landau (RPTU).
Abstract
To improve roller bearing efficiency, it is essential to identify the sources of power losses and quantify them in the design stage, considering different influencing factors. For oil-lubricated bearings, load-independent power losses (𝑃𝐿𝐵0) can be the dominant source of dissipation, especially for high-speed and abundant lubrication. In the present work, 𝑃𝐿𝐵0 of a 32208 tapered roller bearing were measured experimentally under various operating conditions; that is, different rotational speeds, temperatures and geometries of the oil reservoir. A numerical tool, based on computational fluid dynamics, to estimate 𝑃𝐿𝐵0 and provide useful insights to investigate their causes has been developed in the OpenFOAM® environment. Numerical and experimental results show excellent agreement in most of the operating conditions investigated. Oil flows, 𝑃𝐿𝐵0 contributions of different bearing components, and computational effort are discussed in the article.
Al Sonntag Award
The Sonntag Award was established in 1983 and is given to an STLE member or members authoring the best technical paper on solid lubricants published by the society in the year preceding the Annual Meeting.
The winner of the Al Sonntag Award is Investigation on the Tribological Properties of FeS, Cu2S, MoS2, and WS2 Sulfide Films Under Water Lubrication by Jialin Wang of China University of Petroleum and University of Leeds, Bin Han and Zubin Chen of China University of Petroleum, Chun Wang, Anne Neville and Ardian Morina of University of Leeds and Yongsheng Li of Shandong Tianrui Heavy Industry Co., Ltd.
Abstract
FeS, MoS2, WS2, and Cu2S solid films were prepared on CoCrFeNiMo high entropy alloy (HEA), and their tribological performance was tested under water lubrication. The results show that the MoS2/CoCrFeNiMo and the Cu2S/CoCrFeNiMo composite coatings provided excellent tribological properties. The MoS2 film of the MoS2/CoCrFeNiMo composite coating was not worn through at the load of 2 N, providing a reduction of 86% of friction coefficient (μ = 0.03) and 69% of the wear rate (2.68×10−9 cm3/Nm), compared to CoCrFeNiMo coating. At a higher applied load, the anti-wear performance of MoS2 film deteriorated because the MoS2 reacted with oxygen and water to form α-MoO3. α-MoO3 hinders the sliding between layers of MoS2, increasing the third-body abrasive wear of the CoCrFeNiMo coating. Unlike the MoS2/CoCrFeNiMo composite coating, the Cu2S/CoCrFeNiMo composite coating exhibited an improved friction coefficient and wear rate at all loads. This performance is a result of Cu2S reacting with oxygen and water to form Cu and CuO, protecting the CoCrFeNiMo coating from severe wear.