The STLE Compass, May 10, 2011
Micro- and Nanoscale Phenomena in Tribology with Dr. Yip-Wah Chung, Northwestern University
KARA: Hello, I’m Kara Lemar. Welcome to the STLE Compass, brought to you by the Society of Tribologists and Lubrication Engineers. The STLE Compass is your convenient and reliable resource for the latest developments in the tribology community.
This is another episode of The STLE Compass and today the focus is on one of our members, who is a researcher and author. The emphasis is on his status as an author today, and we will get the opportunity to hear him discuss his new book, Micro- and Nanoscale Phenomena in Tribology, and get some insight into its contents. According to the author, the book is based on presentations at the NSF Summer Institute on Nanomechanics, Nanomaterials, and Micro/Nanomanufacturing and it presents the fundamentals of micro- and nanoscale phenomena associated with the tribological interface.
In addition to Dr. Chung, other authors featured in the book include Kathryn J. Wahl, Q. Jane Wang, who is in the process of writing her own book, to be released in 2012, Robert W. Carpick, who is going to be one of our course instructors for the nanotribology course at the Annual Meeting this year, Rachel J. Cannara, Min Zou, Seong H. Kim, and Ashlie Martini, who heads up the Young Tribologists Committee and is helping to organize the nanotribology education course I just mentioned.
The author, Yip-Wah Chung, obtained his PhD in Physics from the University of California at Berkeley. He joined Northwestern University in 1977. He is currently Professor of Materials Science and Engineering and Mechanical Engineering at Northwestern. His research interests are in surface science, tribology, thin films, and alloy design. He was named Fellow, ASM International; Fellow, AVS; and Fellow, STLE. His other awards include the Ralph A Teetor Engineering Educator Award from SAE, Innovative Research Award and Best Paper Award from the ASME Tribology Division, Technical Achievement Award from the National Storage Industry Consortium (now Information Storage Industry Consortium), Bronze Bauhinia Star from the Hong Kong Special Administrative Government, and Advisory Professor from Fudan University. Dr. Chung served two years as program officer in surface engineering and materials design at the National Science Foundation. His most recent research activities are in infrared reflecting coatings, low-friction surfaces, strong and tough coatings, and high-performance alloys.
Today, we will get an inside look into his research and his book, Micro- and Nanoscale Phenomena in Tribology.
KARA: Yip-Wah, welcome to STLE Compass.
YIP-WAH: Happy to be here.
KARA: We’re very glad to have you. So, first can you give us an overview of your research and what you’re working on now?
YIP-WAH: My research area is in surface science and engineering. My most recent interest is to explore different ways to modify surfaces and interfaces and explore how such modifications affect mechanical, tribological, and most recently, biological properties. When I first started at Northwestern, my research was in the study of catalytic phenomena and properties of semiconductor surfaces. It was one of these hallways encounters during the early 1980s, which I had the fortune to talk with Prof. Herbert Cheng, a distinguished and well-respected member of the tribology community. He got me interested in tribology. The rest, as they say, is history.
KARA: Okay, so on that note, has anyone been especially important or influential in your life?
YIP-WAH: Well, I have many mentors who helped shape my professional career over the years. For this program, let me mention just three: the first one is my PhD thesis adviser at Berkeley, Professor Gabor Somorjai, who drilled into me the importance of doing high-quality high-impact research. The second one is Professor Herbert Cheng, who I mentioned earlier influenced me to get into tribology, and Professor Morris Fine, my dear materials science colleague at Northwestern, who inspired me to see the old field of physical metallurgy in a new light. In fact, today, April 12, is Morrie’s 93rd birthday – I dedicate this podcast to him!
KARA: Well, that’s always nice to do. Happy birthday Morrie! So, can you give us a little background on the subject matter addressed in the book?
YIP-WAH: I guess the first thing to think about is that when we talk about tribology, you’re dealing with things that are both large and small. It could be these large bearings and gears in a wind turbine, or small micro-scale components inside a typical digital projector. The successful operation of these devices depends on understanding and controlling interactions occurring at the micro and the nano scale. This field has benefited a great deal from multidisciplinary collaborations, as we witnessed the numerous international conferences and symposia on the subject over the past 20 years. It is with this spirit that eight of us put this book together over the past year. This book represents, in my opinion, the convergence of multiple science and engineering disciplines and the bridging from the macro-scale to the micro-scale.
KARA: How did you get the idea for the book? What inspired you to write it or undertake the project?
YIP-WAH: It is sort of a coincidence how the idea for the book came about. Since 2003, we have been funded by the National Science Foundation to operate the NSF Summer Institute on Nanomechanics, Nanomaterials, and Micro/Nanomanufacturing. The Institute offers short courses on a regular basis as continuing education on different nano-related topics for scientists and engineers. Each short course is taught by a team of speakers who are experts in the field. In 2009, I was approached by Allison Shatkin of Taylor and Francis to write a book on nanotribology. I liked the idea, but this would be a major undertaking. So, I suggested to Allison that perhaps we could piggyback the book project with one of the tribology courses we planned to offer at the Summer Institute in 2010. In this way, each of the book chapters will be authored by the expert speaker: sort of divide-and-conquer approach. We are indeed very fortunate to get the help of 7 experts in the field to not only offer the short course, but also to collaborate on this book project.
KARA: Certainly. So, what topics does the book cover, and why those topics?
YIP-WAH: When we began the book project, the first question we had to address is why another book in tribology? As I mentioned earlier, whether we are dealing with large bearings and gears, or small mirrors in a digital projector, there are these critical phenomena happen at the contacting interfaces, that range from the micro to the nano scale. So, when we put the book together, we needed to start the book with a discussion of the range of conditions spanning the gap from macro to nano scale. This is followed by a continuum overview, then a detailed discussion of the surface energy and forces involved in these tribological contacts, and of course, how we go about measuring these forces. So, that’s sort of the initial part. In the next part, based on the previous section, one is likely to ask the question: how do we control these forces and hence tribological properties? There are two methods of control: physical and chemical modification of surfaces. These two topics are discussed in detail. The final chapter is on molecular dynamics simulation. This is a powerful tool that allows us to not only understand many nanoscale phenomena but also to venture into regimes not easily accessible by experiments. With more powerful computers and smart algorithms, I have no doubt that this method of molecular dynamic simulation will be readily adapted to exploring systems not just for the nano, but the micro scale as well. And that’s the final chapter for this book.
KARA: You mentioned that there are seven other authors. Could you tell us a little bit about the authors and their inclusions in the book?
YIP-WAH: The seven authors, in the order of the chapters are as follows: Kathy Wahl from the Naval Research Lab, who has done some really fantastic work on in situ Raman studies; Professor Q. Jane Wang, my colleague at Northwestern, a long-time member of STLE well-known for her work in lubrication and she’s also a lead editor of a new book, called Encyclopedia of Tribology to be published by Springer in 2012; Professor Rob Carpick from UPenn, the undisputed expert in nanotribology, and his former PhD student, Rachel Cannara from NIST; Professor Min Zou from University of Arkansas, former chair of the STLE nanotribology committee and well-known for her work on micro- and nano-scale surface texturing; Professor Seong Kim from Penn State, he has won many awards for his work on environmental effects in tribology, and last but not least, Professor Ashlie Martini of Purdue University, our up-and-coming young leaders in the STLE community. I am grateful to them for their help and efforts in this book project.
KARA: I’m sure they’ve given a very good contribution. I’ve actually had the opportunity to talk to some of them and it was very beneficial. Indeed, they are very dedicated to their work. IT’s a good collection of authors, I would say.
YIP-WAH: Yep.
KARA: So, for the book, who is the intended audience?
YIP-WAH: Well, this is a book on fundamentals, so the intended audience could include faculty members, postdocs, graduate students, as well as practicing scientists and engineers interested to know more about the fundamentals of tribology in the micro and nano scale.
KARA: So, when will the book be available, do you think?
YIP-WAH: Well, the hope is that it will be available by the next, well, there are two societies I hope that it could be advertised with – one is with the joint conference, the STLE/ASME joint meeting in the fall (IJTC), which I think is October. And then, there is another meeting that we should explore, which is the AVS, which also has its meeting either rin October or early November, and that’s why we would like to target it to be available in October.
KARA: What were some of the difficulties or challenges you faced when trying to compile the book?
YIP-WAH: Well, there was really only one: the usual “operational challenge,” which is quite common, and involves just reminding authors about the deadlines and chasing down manuscripts – nothing unusual. Overall, it has been a very pleasant experience, especially with the capable assistance of the staff at Taylor and Francis.
KARA: Well, that’s always good. I do understand “operational challenges” – there are always deadlines to meet and things to get in. I’m glad that they were helpful there. What are some of the applications that utilize this research, when you’re talking about the micro- and nanoscale?
YIP-WAH: This is a book on fundamentals, so it is of general applicability to different types of devices: from powertrain systems in cars, bearings and gears in turbines, in micro devices known as MEMS used as sensors, to hard disk drives used in computers. Quite a wide range of applications.
KARA: Sure, so some are in consumer applications and others are in other more specialized applications. As far as the field, let’s talk about nanotribology. Have there been any major developments in the field recently, and can you give us some detail?
YIP-WAH: There have been many. For this podcast, I will just mention one. During the past 10 years, we are seeing more and more research investigations on biotribology, in which we study wear and corrosion occurring in orthopedic implants. A typical interface involves a cobalt-chromium alloy rubbing against a polymer substrate in a body fluid with complex chemical composition. And here, you really need to understand interactions happening at the micro- and nanoscale. Being able to control wear and corrosion at such an interface can mean an implant lasting 30 years instead of 10. That’s a big impact, in terms of a person’s health and quality of life. Considering that there are over half a million such operations in the U.S. every year and about one-third are revisions, that means there’s a second surgery, this is quite an important interface!
KARA: Certainly. You want to understand what’s going on there to limit the number of revisions that happen. What do you consider to be the most important issues facing this field today? What does the future look like?
YIP-WAH: I would say there are two issues. One is people. In universities like ours, we are seeing fewer and fewer students interested in tribology research. They are going for, perhaps more of the bandwagon type of research, and that’s a concern. The other is federal funding. We are seeing the prospect of reduction in federal funding in basic research. The problem is that tribology is often considered to be old-fashioned, and core support has not increases over the years. I think we as a community need to do a better job to demonstrate the relevance, excitement, and impact of the field.
KARA: This field has an immense impact in a number of things, let alone just bottom line, looking at cost savings, or even health when you’re talking about biotribology. It’s very important. As far as conclusions, what do you want listeners to take away from today’s discussion?
YIP-WAH: If you look at the field of micro- and nano-tribology, it’s exciting. It involves multiple disciplines. In modern science and engineering, it is at the intersection between two seemingly unrelated disciplines where major discoveries are made and new technological advances are made possible. It is intellectually challenging, it benefits the society and I hope that’s the key message that the listener would take away from today’s discussion.
KARA: Well, I look forward to seeing your book and I’m sure a lot of people are interested in reading it and will pick it up. Thank you so much for your time. We appreciate it.
YIP-WAH: And I was glad to be here today.
KARA: I’m Kara Lemar. For more news, information and research on micro- and nanoscale applications, please visit our website. You can also get more on Dr. Chung and his work at the Northwestern website. Remember, if you are an STLE member, you can purchase Dr. Chung’s book at a discount when it becomes available. You can look up the book in the STLE Store later this year at stle.org, or for more information, you can visit the publisher, CRC Press, at their website, at crcpress.com. Thank you for joining us today. This has been another episode of The STLE Compass, pointing you in the right direction.

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