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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Temperature-dependent phonon dynamics of Ag3PO4 microcrystals
J V B Moura1, C D de Abreu Lima2, E A O Melo1
1Laboratório de Caracterização de Materiais, Centro de Ciências e Tecnologia, Universidade Federal do Cariri, CEP 63048-080, Juazeiro do Norte, CE, Brazil.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|December 28, 2020
Summary
Silver orthophosphate (Ag3PO4) microcrystals exhibit a reversible first-order phase transition around 500-515°C. This transition, confirmed by Raman scattering and DSC, involves PO4 tetrahedral distortion due to decreased crystalline order.
Area of Science:
- Materials Science
- Solid State Chemistry
- Crystallography
Background:
- Silver orthophosphate (Ag3PO4) is a material with potential applications.
- Understanding its thermal properties is crucial for its use.
- Phase transitions can significantly alter material properties.
Purpose of the Study:
- To investigate the temperature-dependent behavior of silver orthophosphate (Ag3PO4) microcrystals.
- To identify and characterize any phase transitions using in situ Raman spectroscopy.
- To correlate structural changes with observed phase transitions.
Main Methods:
- Synthesis of Ag3PO4 microcrystals via precipitation.
- Characterization using powder X-ray diffraction (XRD), SEM, Raman, IR spectroscopy, and DSC.
- In situ temperature-dependent Raman scattering to study phonon dynamics.
Main Results:
- A reversible first-order phase transition was observed in Ag3PO4 microcrystals between 500-515°C (Phase I to Phase II).
- The transition exhibited temperature hysteresis during heating and cooling cycles.
- DSC analysis confirmed the phase transition temperature range and reversibility.
Conclusions:
- The reversible phase transition in Ag3PO4 is linked to the distortion of PO4 tetrahedral symmetry.
- Decreased crystalline order contributes to the observed phase transition.
- Temperature-dependent Raman spectroscopy is a powerful tool for studying phase transitions in materials.
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