Jan Schwenger

Project description

The mechanical response of homogeneous bulk materials to external stimuli is well described by the constitutive laws of continuum mechanics. However, the small scale deformation behavior of (sub-) micron-sized particles is fairly distinct from the bulk due to internal and external interfaces as the size dimensions are close to the characteristic length scale (e.g. dislocation spacing) of underlying physical (deformation) processes. Especially in the field of particle technology, where particle-particle and particle-substrate interactions govern the final product properties, the mechanical deformation behavior of individual (sub-) micron-sized particles in contact (and ensembles thereof) is of great interest and relevance [1,2].

In this context, dedicated and precise in situ SEM compression devices are needed which provide access to a variety of mechanical quantities such as Young’s modulus and breakage probability for particle diameters ranging from few tens of nanometers up to hundreds of micrometers. In order to improve noise level, data point density, deflection and force resolution as well as the number of possible measurement methods, a new setup is under development. In comparison to our existing SEM-supported manipulation device [3], a capacitive coupled closed loop XYZ-piezo stage allows not only more precise deflection in force direction, but also well-defined movements and positioning in lateral coordinates. In addition, a sophisticated measurement software will combine all positioning and data acquisition capabilities, leading to both a better motion control of the probe and a higher level of data coupling.

Fig. 1: Conceptual layout of the new SEM supported in situ micromanipulator.

References

[1] J. Paul et al., Advanced Powder Technology 25 (2014) 136.
[2] J. Paul et al., Powder Technology 286 (2015) 706.
[3] S. Romeis et al., Review of Scientific Instruments 83 (2012) 95105.