Dr. Lars Jeurgens, Empa - Swiss Federal Laboratories for Materials Science and Technology, Laboratory for "Joining Technologies & Corrosion" - "Surprises at interfaces in nanomaterials"



The energetics of nanomaterials are typically dominated by (excess) surface and/or interface energy contributions. Hence the thermodynamics of reactions and phase transformations in nanostructured materials and thin-film systems generally deviate from the 'expected' behaviors for the bulk materials. Moreover the short diffusion distances in combination with the high density of surfaces and interfaces enable much faster kinetics for thermodynamic equilibration, which makes artificial, nano-sized systems very prone to degradation.

This talk will address recent advances in the thermodynamic description of reactions and phase transformations in nanomaterials. The principles and guidelines to construct generally applicable thermodynamic model descriptions of interface-controlled reactions and microstructural evolutions will be outlined [1].

As an example, model predictions on the critical thickness for the amorphous-to-crystalline transition of ultrathin (< 10 nm) oxide films on their metals are compared with experiments [1]. Furthermore, predictions and experimental verifications of the Al-catalyzed crystallization of amorphous Si thin films are presented, which allow the low-temperature (< 200 oC) manufacturing of high-efficiency solar cells and crystalline-Si-based nanostructures on cheap and flexible substrates such as glasses, plastics and possibly even papers [2]. Finally, recent advancements in the interfacial design of nanostructured filler materials for joining at ever-lower temperatures much below the bulk (eutectic) melting point will be highlighted [3].

Selected References

[1] L.P.H. Jeurgens, Z.M. Wang, E.J. Mittemeijer, Thermodynamics of reactions and phase transformations at interfaces and surfaces, Int. J. Mater. Res. 100 (2009) 1281.

[2] Z.M. Wang, J.Y. Wang, L.P.H. Jeurgens, E.J. Mittemeijer, Tailoring the ultrathin Al-induced crystallization temperature of amorphous Si by application of interface thermodynamics, Phys. Rev. Lett. 100 (2008) 125503.

[3] J. Janczak-Rusch, G. Kaptay, L.P.H. Jeurgens, Interfacial design for joining technologies - An historical perspective, Journal of Materials Engineering and Performance (2014) [DOI: 10.1007/s11665-014-0928-5].

dr hab. Jacek Tarasiuk
Wydział Fizyki i Informatyki Stosowanej AGH, Katedra Fizyki Materii Skondensowanej
"Mikrotomografia rentgenowska w badaniach materiałowych i biofizycznych."



W pierwszej części zaprezentowane zostaną podstawy fizyczne mikrotomografii rentgenowskiej, omówione obszary jej zastosowań, najważniejsze zalety i ograniczenia. W drugiej części przedstawione będą badania prowadzone w Laboratorium Mikro i Nano Tomografii AGH.

Prof.dr hab. Józef Spałek
Instytut Fizyki UJ
"Na drodze do teorii nadprzewodnictwa niekonwencjonalnego."