title collage
Photo of James Zhijian Shen

Prof. James Zhijian Shen


to his website
 
Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Sweden
http://www.mmk.su.se/

Curriculum Vitae

Dr James Zhijian Shen is an expert in ceramics science and engineering, specializing in designing and synthesising of advanced ceramics and composites with tailored microstructures and chemistry for structural and functional applications.  He holds a position as a Professor, Noble Biocare Chair of Materials Innovation, at Arrhenius Laboratory, Stockholm University, where he also serves as an area manager of Biomaterials in the Berzelii Center EXSELENT on Porous Materials strategically supported by the Swedish Governmental Agencies VR and VINNOVA. He has authored more than 200 published papers on ceramics and ceramic processes. He was educated in China, received his PhD on Materials Physics and Chemistry in 1990 and was appointed as an Associated Professor in 1992 at Zhejiang University. In 1993, he moved to Sweden, initially as a postdoctoral researcher, latterly was appointed as a senior researcher, Associated Professor and Professor in the same Institution he has always been working till now.

His Topic of Materials' Days 2010:

Micron-defects mask the potentials of nanoceramics:


Abstract:
Microstructural defects in micron-scale are not intrinsic features of nanoceramics. They are types of processing defects introduced during ceramics processes. Once formed, they are inheritable, i.e. they are carried on during the processes and remain in sintered bodies thus to impair the performances of nanostructured ceramics that otherwise would be enhanced by their nano-sized grain structure and/or associated high interface content. In most of the cases, micron-defects are already formed during the powder forming or powder granulation processes, with more addition during the green body forming processes. Sintering can hardly completely heal micron-defects even under pressure, with increased challenge when rapid sintering techniques are employed for densification. In general, it is much more difficult to handle the micron-defects in nanoceramics due to the inherent large sintering driving forces associated with the nanoparticles. In this presentation examples will be given to classify the types of micron-defects encountered during the processing of nanoceramics. The influence of micron-defects on various performances of nanoceramics will be discussed. Ways and means of avoiding and destroying micron-defects during the entire ceramic processing cycle will be suggested in order to explore the full potentials of nanoceramics.