In situ ptychographic x-ray nanotomography of temperature-controlled crystallization processes

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Dynamic processes like crystallization are crucial for material properties but difficult to study due to their transient and multi-scale nature.
• Current in situ methods lack the combined resolution, temporal control, and environmental range needed to capture these phenomena.
• Understanding these transformations is key to designing advanced engineered and natural materials.

Purpose of the Study:

• To present an integrated platform for in situ time- and temperature-resolved ptychographic X-ray nanotomography.
• To demonstrate the platform's capability in visualizing dynamic material transformations under realistic conditions.
• To provide unprecedented insights into crystallization pathways and Ostwald ripening.

Main Methods:

• Development of an integrated platform for in situ time- and temperature-resolved ptychographic X-ray nanotomography.
• Tracking the crystallization of amorphous calcium carbonate from room temperature to 500°C.
• Acquisition of quantitative tomograms at five-minute intervals to create a 4D dataset.

Main Results:

• Revealed multiple simultaneous crystallization pathways and rare, transient events during amorphous calcium carbonate transformation.
• Observed the formation and recrystallization of metastable calcium carbonate hemihydrate, previously only seen in stabilized systems.
• Demonstrated the role of volume defect evolution and structural rearrangements in Ostwald ripening.

Conclusions:

• The developed platform enables in situ visualization of material transformations with nanoscale resolution and minute-scale temporal resolution.
• Provides critical insights into the mechanisms governing material structure and functionality during dynamic processes.
• Offers a general method for studying a wide range of material transformations across various length and time scales.