Three-dimensional electron diffraction on clinkers: the belite α'_H incommensurate modulated structure.

Area of Science:

• Materials Science
• Crystallography
• Mineralogy

Background:

• Traditional X-ray diffraction struggles with complex cement phase mixtures due to overlapping reflections.
• 3D electron diffraction offers a promising alternative for analyzing individual cement particles.
• Automated data acquisition in electron diffraction enhances systematic crystallographic studies.

Purpose of the Study:

• To investigate crystalline phases in commercial cement clinkers using 3D electron diffraction.
• To characterize the incommensurately modulated structure of the α'H polymorph of Ca2SiO4 (belite).
• To demonstrate the utility of 3D electron diffraction for systematic crystallographic analysis in the cement industry.

Main Methods:

• Utilized 3D electron diffraction with automated data collection and processing.
• Applied superspace formalism to solve and refine the modulated structure of belite.
• Employed harmonic and crenel functions within the superspace group Pnma(α00)0ss.

Main Results:

• Successfully characterized various crystalline phases in commercial cement clinkers.
• Solved and refined the incommensurately modulated structure of the α'H belite polymorph.
• Provided a comprehensive description of belite polymorphs based on the modulated structure.

Conclusions:

• 3D electron diffraction is a powerful tool for detailed crystallographic characterization of cement materials.
• The study provides a complete description of the modulated structure of α'H belite using superspace formalism.
• This technique holds significant potential for advancing research and quality control in the cement industry.