Ultra-low friction requirements in automotive, aerospace, defense and renewable energy industries has  
pushed research in developing new coatings, lubricants and materials that exhibit super lubricity.  
Advanced sensors and characterization techniques are required to study the reliably of tibological  
surface and their interactions that experience super lubricity. Most of the experimental work in super  
lubricity studies has been limited to small scale tests through Atomic Force Microscope (AFMs) or  
Surface force apparatus (SFAs). These instruments offer extremely precise force measurements, but the  
forces are limited to the nano and micro ranges. These methods offer indirect friction measurements  
derived from frequency shifts with certain assumptions rather than a direct measurement. Additionally,  
the area characterized by the AFM is also very small and microscopic by nature and only AFM tips can be  
used as one of the materials in the tribo-pair. Even though understanding the super lubricity interactions  
at atomic scale is necessary to grasp the mechanisms involved, it cannot aid in the implementation of  
the technology at a macro scale. The present study addresses this challenge of scaling and  
characterization of super lubricity. The study uses an advanced capacitance sensors developed for  
tribological characterization of macroscopic samples exhibiting ultra-low friction under ambient or  
controlled environmental conditions. These sensors are robust and offer significantly enhanced factor of  
safety compared to the traditional strain gauge sensors commonly used in tribology. The sensors also  
offer enhanced signal to noise ratios with background noise in the order of 0.01% of the full scale. The  
stability of the sensor is shown by continuous measurements over a period of twenty-four hours  
demonstrating low noise and negligible drifts throughout the test. The system designed takes advantage  
of the high resolution provided by the capacitance sensors and measures friction and normal force  
independently with high accurately. The system is material and geometry independent and a range of  
samples can be easily tested. The efficiency of the sensor is demonstrated through a ball-on-disk test  
where the friction was recorded for a ceramic ball sliding on a ceramic disk while lubricated with  
phosphoric acid. A minimum coefficient of friction of 0.004 was observed during the test. Further, an  
integrated 3D profilometer was used to study the wear tracks after the tribological tests. The low  
friction measurements, floor noise and drift measurements demonstrate the accuracy and reliability of  
the advanced platform to characterize super lubricity on macro scales for a range of samples and load.


Advanced Capacitance Sensors for Tribological Characterization of Superlubricity Conditions

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

IMECE2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.