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Garabedian Udel 0060 A DIRECT EXPERIMENTAL LINK BETWEEN ATOMIC-SCALE AND MACROSCALE FRICTION by Nikolay T. Garabedian A dissertation submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering Spring 2019 © 2019 Nikolay T. Garabedian All Rights Reserved A DIRECT EXPERIMENTAL LINK BETWEEN ATOMIC-SCALE AND MACROSCALE FRICTION by Nikolay T. Garabedian Approved: __________________________________________________________ Ajay K. Prasad, Ph.D. Chair of the Department of Mechanical Engineering Approved: __________________________________________________________ Levi T. Thompson, Ph.D. Dean of the College of Engineering Approved: __________________________________________________________ Douglas J. Doren, Ph.D. Interim Vice Provost for Graduate and Professional Education I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ David L. Burris, Ph.D. Professor in charge of dissertation I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ M. Zubaer Hossain, Ph.D. Member of dissertation committee I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ Chaoying Ni, Ph.D. Member of dissertation committee I certify that I have read this dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy. Signed: __________________________________________________________ Erik Thostenson, Ph.D. Member of dissertation committee ACKNOWLEDGMENTS I would like to sincerely acknowledge all people and institutions that were part of my PhD degree. I am first grateful to the institutions and organizations that provided financial support for my research: the National Science Foundation, the Society of Tribologists and Lubrication Engineers, the Gore Fellowship through the College of Engineering at the University of Delaware, the University of Delaware Office of Graduate and Professional Education, and the Department of Mechanical Engineering. I would like to thank my dissertation committee members for the valuable discussions we had during my time as a student: Drs. M. Zubaer Hossain, Chaoying Ni, Erik Thostenson. My doctoral work would have not been possible without the invariable support from the Department of Mechanical Engineering: Lita Toto, Lisa Katzmire, Ann Connor, Amy Adams, Melissa Arenz. The people that support the Keck Advanced Microscopy Facility were another vital part of my experimental work: Jen Sloppy, Thomas Barkley, Yong Zhao. I need to express my enormous gratitude to the staff at the Department of Mechanical Engineering Machine Shop: Scott Nelson and Jeff Ricketts. Their help and expertise improved my designs and taught me engineering skills that I could have never obtained otherwise. I also need to thank the community of researchers and engineers that are part of the broader tribology community for their advice whenever we have met at conferences. iv My collaborators on projects and papers were another vital part of my work at the University of Delaware and I thank them for inspiring scientific interest and allowing me to learn about fields I never expected to venture into: Drs. Jillian Emerson, Brandon McClimon, James Hilbert, Harmandeep Khare, Eric Furst, Thomas Epps, III, Robert Carpick, Gary Doll, Kevin Dicker, Xinqiao Jia, Jing Qu, David Martin, and especially Brian Borovsky for bringing his character and originality of research to our lab for a full summer. During my doctoral training I spent the most time with my labmates. Thank you for all your support and richness of experiences you provided me with: Dr. Jiaxin Ye, Dr. Axel Moore, Dr. Diana Haidar, Dr. Benjamin Gould, Arnab Bhattacharjee, Istiaque Alam, Aman Garodia, Viraj Sachpara, Steven Voinier, Jamie Benson. And although a PhD required my full attention and I very often was not fully available to my friends, these people were there and helped me get through the marathon which this degree represents: Erisa Saraçi, Albraa Jaber, Georgi Manolov, Brandie Pugh, Tugce Yuksel, Mariya Petrova, Anita Toncheva, Milen Kisov, Raja Ganesh, Shyamola Athaide, Daniela Hristova, Eriselda Danaj, the Kutsilevi family, Stephen Berniker, Yulian Karapetkov, Rohit Kakodkar, Mariana Stoitseva, Swing Club, Rexhi, Adam Stager, Krasimir Dimitrov, Stoyan Yanchev, Diana Gomes. I thank my family members for their unconditional support and understanding during my degree: Tzveta Garabedian, Takvor Garabedian, Tanya Petrova, Martina Garabedian, Mariya Petrova, Nikolay Petrov, Mitka Garabedian, Margarita Gesheva, Stoyan Geshev, Sofia Gesheva, Krasimir Geshev, Stefan Garabedov, Toni Garabedova. v Finally, I need to express my deepest gratitude to my mentor Dr. David L. Burris for guiding me through his insatiable interest for scientific discovery, eagerness for new lab endeavors and dedication to my progress. v i TABLE OF CONTENTS LIST OF TABLES ......................................................................................................... x LIST OF FIGURES ....................................................................................................... xi ABSTRACT ................................................................................................................ xxi Chapter 1 INTRODUCTION .............................................................................................. 1 2 PROBLEM STATEMENT AND OBJECTIVES .............................................. 9 3 QUANTIFYING, LOCATING, AND FOLLOWING ASPERITY SCALE WEAR WITHIN MACROSCALE CONTACT AREAS ................................ 11 3.1 Abstract .................................................................................................... 11 3.2 Introduction ............................................................................................. 12 3.3 Methods ................................................................................................... 15 3.3.1 The Topographic Difference Method .......................................... 15 3.3.2 Wear Volume Uncertainty Characterization ............................... 16 3.3.3 Validation Experiment ................................................................. 18 3.3.4 Quantifying and Correcting Repositioning Error ........................ 20 3.4 Results ..................................................................................................... 22 3.4.1 Repositioning Uncertainty ........................................................... 22 3.4.2 Validation Results ....................................................................... 23 3.4.3 Wear Mapping ............................................................................. 25 3.5 Discussion ................................................................................................ 30 3.6 Conclusions ............................................................................................. 32 4 MICROTRIBOMETRY ................................................................................... 34 4.1 Setup and Calibration .............................................................................. 34 4.2 Friction Force Dependence on Material and Probe Size ......................... 37 vii 5 INTEGRATED QCM-MICROTRIBOMETRY: FRICTION OF SINGLE- CRYSTAL MOS2 AND GOLD FROM mm/s TO m/s .................................... 45 5.1 Abstract .................................................................................................... 45 5.2 Introduction ............................................................................................. 46 5.3 Methods ................................................................................................... 49 5.3.1 Materials ...................................................................................... 49 5.3.2 Instruments .................................................................................. 51 5.3.3 Measurement and Analysis Methods ........................................... 55 5.3.3.1 QCM-based Force Measurements ................................ 55 5.3.3.2 Spring-based Force Measurements ............................... 57 5.3.4 Experimental Design ................................................................... 57 5.4 Results ..................................................................................................... 59 5.4.1 Benchmarking Friction with the QCM ........................................ 59 5.4.2 The Effect of Integration on the QCM Measurement ................. 62 5.4.3 Comparing QCM and Spring-based Microtribometry ................ 63 5.4.4 Effects of Other Experimental Variables .................................... 64 5.5 Discussion ................................................................................................ 66 5.6 Conclusions ............................................................................................. 70 6 HIGH-FORCE
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