Electron diffraction characterization of nanocrystalline materials using a Rietveld-based approach. Part I....

Area of Science:

• Materials Science
• Crystallography
• Nanotechnology

Background:

• Transmission electron microscopy (TEM) is crucial for characterizing nanocrystalline materials.
• Electron powder diffraction (EPD) combined with spectroscopy identifies crystalline phases and microstructural features.
• EPD offers potential similar to X-ray powder diffraction (XRPRPD) for detailed material analysis.

Purpose of the Study:

• To adapt full-pattern fitting procedures, commonly used for XRPD, to EPD analysis.
• To accelerate the characterization of nanocrystalline materials, especially metastable structures.
• To leverage EPD's reduced sampling volume for detecting surface alterations.

Main Methods:

• Extending full-pattern fitting procedures from XRPD to EPD.
• Implementing Rietveld refinement for quantitative analysis of EPD data.
• Developing a reliable calibration protocol to account for instrumental broadening.

Main Results:

• Demonstrated methodology for determining instrumental broadening in EPD.
• Successful quantitative analysis of EPD data using Rietveld refinement.
• Identified key characteristics for effective calibration standards in EPD.

Conclusions:

• The adapted methodology enhances the speed and detail of nanocrystalline material characterization using EPD.
• Accurate calibration is essential for separating instrumental effects from material properties.
• EPD analysis provides unique insights into surface phenomena and microstructural details.