Research of the structure and dynamic interactions of particles in the Li0.42K0.58NO3- R (R = α-Al2O3, γ-Al2O3, SiO2) and (LiNO3-LiClO4) - γ-Al2O3 composites in various temperature conditions and phase states.

The paper presents a comprehensive study of the Li0.42K0.58NO3- R (R = α-Al2O3, γ-Al2O3, SiO2) and (LiNO3 - LiClO4) - γ- Al2O3 composite salt systems by vibrational spectroscopy, X-ray diffractometry, and differential scanning calorimetry. According to the results of Raman spectra and XRD analysis, it has been found that in the case of a sufficiently small filler (15 nm-γ-Al2O3 and SiO2), an amorphous phase appears, both for systems based on Li0.42K0.58NO3 and for the nanocomposite based on (LiNO3)0.5-(LiClO4)0.5. In the case of nanocomposites based on the Li0.42K0.58NO3 system, this additionally leads to the formation of the metastable KNO3 (R3m) phase. The temperature changes in the half-widths of the corresponding bands of the Raman spectrum during the transition from a solid-phase to a molten state become less significant as the concentration of the oxide filler increases. At x ≥ 0.7, on the temperature dependences of the half-width of the ν1 (A) band in the vicinity of the melting point, only a small kink characteristic of amorphous systems is noticed. This is confirmed by the results of thermal analysis. It has been found that the solid filler has a different effect on the processes of orientational and vibrational relaxation in the molten phases of the studied NIS, namely, the orientational mobility of NO3- decreases, while the relaxation rate of its vibrational excitation increases.