Keynote Lecture: ZnP-ZnO dual-phase coatings on Zn foams with excellent antibacterial ability and biocompatibility for biodegradable orthopedic applications

Abstract: Zinc (Zn)-based biomaterials are receiving increasing attention as biodegradable metals due to their more suitable degradation rate than magnesium, iron, and their alloys. In this study, zinc phosphate (ZnP), zinc oxide (ZnO), and their dual-phase coatings were fabricated on a pure Zn foam via electrochemical anodization and subsequent phosphating. The dual-phase-coated foam sample showed a regular, almost spherical open-cellular interconnected porous structure with ~ 8 μm thick surface layer of ZnO and ZnP. Compressive test results showed that the dual-phase-coated foam sample exhibited a compressive yield strength of 1.8 and 1.1 MPa, a plateau strength of 2.9 and 2.7 MPa, and a compressive strain of 90% before and after 30 d immersion in Hanks’ solution. Biocompatibility assessment showed that the dual-phase-coated foam sample showed excellent cell viability toward MC3T3-E1 and MG 63 cells in both direct and indirect cell assays, and its 12.5% concentration extract showed ~ 107% cell viability of MC3T3-E1 cells and ~ 101% cell viability of MG 63 cells, indicating a positive effect on cell survival and proliferation. Moreover, the dual-phase-coated Zn foam sample exhibited effective antibacterial ability against S. aureus. Overall, the ZnO-ZnP dual-phase-coated Zn foam can be considered a promising biodegradable scaffold biomaterial for orthopedic applications.

Keynote Lecture: Manufacturing issues with equiatomic FeCo-2V alloy as a soft magnetic material: effect of laminate preparation and annealing treatment

Abstract: FeCo-2V alloy is a soft magnetic material commonly used in high performance electrical machines in form of a laminate made of stacked thin sheets. Laminate preparation inevitably induces defects along the cutting edges, which may deteriorate the magnetic properties of the laminate. We have explored various laminate cutting methods, viz., mechanical punching, electrical discharge machining (EDM), and laser cutting, to assess their impact on the magnetic properties of the laminates. The effect of annealing treatment before and after the cutting process was also studied. The magnetic performance is explained via the grain size and local misorientation along the cut-affected zones. Our study indicates that grain boundary and local misorientation within the grains are key factors when assessing the deterioration of the soft magnetic properties. It was found that laser cutting with a post-cutting annealing treatment leads to the best magnetic performance among all investigated manufacturing routes. This is explained by the largest grain size along the cutting edges (even larger than that in the central unaffected area), together with minimum local misorientation after the post treatment.

Biography: Prof. Chen obtained his PhD at the University of Reading, UK, under the sponsorship of an Overseas Research Scholarship (ORS) by the Committee of Vice Chancellors and Principals (CVCP) in the UK, and a European Union research grant. In April 1997, he joined the newly established Institute of Materials Research and Engineering (IMRE), a national research institute funded by Singapore government. In March 2000, he moved to Nanyang Technological University (NTU) as an Assistant Professor and has been promoted to Associate Professor and Professor in the School of Materials Science and Engineering. Since joining NTU, Prof. Chen has graduated 35 PhD and 6 MEng students. Prof. Chen’s research interests include 1) Surface Engineering and 2) Mechanical & Long-term Behavior of Materials. He is an author of over 400 peer-reviewed journal papers, 5 book chapters and 7 granted patents. According to Google Scholar, his journal articles have received over 30,000 citations with h-index of 90. He has been recognized by Clarivate as a globally Highly Cited Researcher since 2019.

Keynote Lecture: Surface Engineering Design on Alleviating Fretting Wear

Abstract: This paper detail reviewed the progress of two-types fretting map theory (running condition fretting map-RCFM and material response fretting map-MRFM), and outlines the protection strategy of fretting wear according to the fretting map theory. Several surface engineering techniques (such as PVD, laser surface modification technology, bonded solid lubricant coating, thermal spraying coating, and micro-arc oxidation coating) against fretting wear are reviewed, several mechanisms to alleviating fretting wear are proposed as well as a collection of practical examples of surface engineering designs to anti-fretting wear. Base on the review of previous studies, mechanisms of surface engineering technologies for alleviating fretting wear have been proposed. In addition, the content and process of surface engineering design are introduced in this paper. Finally, taking the locking pin of variable gauge train as an example, the process of surface engineering design is further expounded.

Biography: Dr. Min-hao ZHU became a professor of Southwest Jiaotong University in 2001, and became a Chief Professor of Southwest Jiaotong University in 2015. He has become a Yangtze River Scholar Professor of Ministry of Education of China in 2014, has acquired a National Natural Science Fund for Distinguished Young Scholars of NSFC in 2010.
      Over the past two decades, he has mainly studied on fretting wear, fretting fatigue, tribology of railway and surface engineering. His doctoral dissertation was won a prize of the Author of National Excellent Doctoral Dissertation of China in 2005. He won a SNECMA AWARD in 2003 (SNECMA is a French company, and a famous aerospace engine manufacturing company in the word). He as the second honorees received an award of the Second Prize of National Natural Science of China in 2006, which was on study of fretting wear. He has issued 4 books，more than 500 papers and was licensed 70 patents of China.
      In areas such as rail transportation, aerospace and nuclear power has carried out a large number of failure analysis work, including bolts and their locking structures, axles of high speed railway and urban rail transit vehicles, bearings of trains and aero-engines, catenary parts of railway, motor shafts and electric plug-in, diesel engine parts, nuclear steam generator heat transfer tubes, brake pieces, rails and turnouts, the train wheels, etc..