Scientific publication

A new ball-on-disk vacuum tribometer with in situ measurement of the wear track by digital holographic microscopy

Written by Bastian Meylan, Dario Ciani, Bin Zhang, Etienne Cuche and

Outline

This contribution presents a new ball-on-disk vacuum tribometer with in situ measurement of the wear track by digital holographic microscopy. This new tribometer allow observing the evolution of the wear track in situ and in real-time. The method combines a high vacuum high temperature ball-on-disk tribometer with a digital holographic microscope (DHM). The machine was tested and validated by taking DHM images during wear tests in vacuum at 2·10-6 of polished 100Cr6 steel disks.

Reference

B. Meylan, D. Ciani, B. Zhang, E. Cuche, and K. Wasmer, A New Ball-On-Disk Vacuum Tribometer With In Situ Measurement of The Wear Track by Digital Holographic Microscopy, Surf. Topogr.: Metrol. Prop., Vol. 5, paper ID: 044004, 2017, doi: https://doi.org/10.1088/2051-672X/aa854a

Supplementary data

https://www.empa.ch/documents/55898/1337782/DSC_9930_2.jpg/dafa1ce3-7703-4a1a-80db-4c68cf5c7e5d?t=1502290285000
https://www.empa.ch/documents/55898/1337782/DSC_9940_2.jpg/f2898c1f-ccb3-4afd-b9cc-f98065305cd8?t=1502290286000
Pictures of setup, showing the positioning of the optical well and the tribometer arm above the sample. The sample holder is surrounded by the heating element, not visible on the picture as the heating element is surrounded by the cooling housing.

 

Evolution of the wear for 1 to 500 Laps. This video shows the complete evolution of the wear track from the first lap to lap 500. The picture are taken at the same position by triggering of the DHM by the tribometer rotation. Bellow, is the average profile made in the black box above. Test conditions: 1N load with a rotation velocity of 1cm/s at room temperature in vacuum.

 

 

Evolution of the wear along the wear track. This video shows the evolution of the wear track for 100 pictures taken along the wear track.The picture are taken at 12.5 images /s with a rotation speed of 0.17cm/s. Bellow, is the average profile made in the black box above. Test conditions: 1N load with a rotation velocity of 1cm/s at room temperature in vacuum for 50 laps

https://www.empa.ch/documents/55898/1337782/Sequence+variation.png/6763c01a-0da5-43a3-8628-fbc6b2393272?t=1502290286000
Evolution of the ridge volume and wear volume along the wear track for 100 images. This shows clearly small oscillations of the wear track along the track. This shows that there is a small risk of underestimating or overestimating wear if only a single measure is taken