In-situ Characterization of Phase Transitions in Nanostructures

ZHM research project

From 01.01.23 to 30.06.23, the ZHM supported a joint research project of the Institute of Advanced Ceramics and the Institute of Polymers and Composites at the Hamburg University of Technology (TUHH) and the Institute of Materials Mechanics at the Helmholtz-Zentrum Hereon GmbH (Hereon) for the in-situ characterization of phase transitions in nanostructures. The joint project has succeeded in establishing a process for the in-situ characterization of phase transitions at high temperatures and under controlled atmosphere using high-resolution, fast-scanning in-situ X-ray diffraction. For this purpose, the XRD measurement system of the Advanced Ceramics group was optimized and tested with respect to high-speed measurement parameters for various nanoporous materials. A high-temperature measurement setup with test dome was put into operation, which allows samples to be examined in-situ at up to 900 ◦C under gas atmosphere and vacuum conditions. The functionality of the XRD in situ measurement setup was successfully demonstrated on the reversible vanadium dioxide phase change from the monoclinic to the rutile phase.

In addition, the foundation stone was laid for the in-situ measurement of the zinc oxide/ZnO template for aerographite (aeroG) CVD synthesis. For this purpose, the CVD mini-reactor developed in the Polymers and Composites Group, which can be put into operation in the XRD measuring room, was further optimized. The different material characteristics of ZnO and aeroG were analyzed at the XRD, process parameters were defined and the first
intermediate synthesis stages were investigated.

The successful collaboration between the three research groups was funded as part of the preparations for the application for the "BlueMat" cluster of excellence and is a successful example of the overarching collaboration in the Hamburg metropolitan region.