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In-situ Element Mapping at Elevated Temperatures

The use of heating holders, or any other in-situ reaction cells, which are suitable for electron microscopy and EDS, allows to monitor the effect of materials treatment in-situ or in-operando in the electron microscope. This means that information on changes in structure and element composition is available qualitatively and quantitavely with high spatial resolution.

Electron microscopy is the means to study materials with high spatial resolution. Energy dispersive X-ray spectroscopy (EDS) in the electron microscope allows to map element distributions on the nanoscale. And finally, the use of heating holders, or any other in-situ reaction cells, which are suitable for electron microscopy and EDS, allows to monitor the effect of materials treatment in-situ or in-operando in the electron microscope. This means that information on changes in structure and element composition is available qualitatively and quantitavely with high spatial resolution.

EDS element maps for monitoring particle structure and composition changes during heating from 800°C to 1000°C

A Pt-Pd test specimen was investigated at various elevated temperatures using the Wildfire, a MEMS based heating holder from DENS solutions and a Bruker QUANTAX EDS system with an XFlash® 6T 30 detector on a standard scanning transmission electron microscope (STEM). The detector with 30 mm2 active area achieves a collection angle of 0.09 sr at a take-off angle of 22° in the STEM used. The specimen holder is of a new special design for improved thermal stability in z-direction, which allowed to monitor the same specimen area easily between room temperature and 1000°C. The EDS system provided suitable mapping times of a few min element map at each temperature step.
Figure 1 shows the development of the Pt-Pd nanoparticles with rising temperature.
Figure 2 demonstrates how the development of the particle number size and composition can be monitored quantitatively using PCA based phase analysis and arealy coverage.

EDS element maps at different temperatures and the areal coverage development of 3 assigned phases: substrate, Pd and Au