Structural Transformations in SrCO₃ + V₂O₅ Mixture During Ball‐Milling Revealed by Raman Spectroscopy.

Mechanochemical (MC) methods have emerged as an alternative approach to induce chemical reactions in various systems offering promising opportunities for innovative energy‐efficient synthesis methods of polycrystalline materials. MC reactions can proceed via the pathways different to those in the conventional solid‐state synthesis methods, through new metastable intermediate and often amorphous phases. Fundamental understanding of reactivity of solids during this process is required for knowledge‐guided synthesis procedures. In this study, we have investigated the structural changes in SrCO3 + V2O5 mixtures upon ball‐milling and the feasibility or MC synthesis of the tertiary vanadium oxide, SrV2O6 that is conventionally prepared by solid‐state synthesis above 600°C. We varied the milling speed, duration, and ball diameter to examine the effects of the milling parameters on the reaction intermediates and outcomes. The phase composition of the intermediate and final mixtures was characterized using X‐ray diffraction, thermogravimetry combined with differential scanning calorimetry (TGA‐DSC), and Raman spectroscopy. Although powder X‐ray diffraction was used to identify the evolution of the crystalline phases, the intermediate milling products and the final phase obtained in the milling were mostly amorphous, and the Raman and TGA‐DSC analyses provided indispensable evidence of the presence of amorphous SrV2O6 in the mixtures as the main phase. The polycrystalline vanadate product was obtained after a short thermal treatment of the ball‐milled powders at 420°C with the average particle size smaller than that of the sample synthesized via the solid‐state method. [ABSTRACT FROM AUTHOR]