This work is aimed at studying thefundamentals ensuring the formationof high-quality functional printed copper layers at low temperatures.The paper describes the decomposition of copper formate and its ligand-basedcomplexes: ammonia, ethylamine, diethylamine, and pyridine. Structuraland thermal features of the samples were studied by differential thermalanalysis, thermogravimetric analysis, and X-ray diffraction analysis.Based on the results of experimental data and quantum-chemical calculationsas well, the main features of the reactions of decomposition of thestudied samples have been proposed. Aspects of the main factors reducingthe decomposition temperature of complex compounds have been identifiedand described. Based on the results of the study, a self-consistentmodel which describes the limits of the existing models of the decompositionprocess of copper formate and its complex compounds is proposed inthe work.

The effect of mechanical activation on the structure and conductivity of the KNO 3 –Al 2 O 3 composite is considered. The analysis of DSC curves measured in the course of heating of the 0.5KNO 3 –0.5Al 2 O 3 composite shows that the enthalpy of phase transitions decreases with the increase in the time of mechanical activation. Based on the X-ray diffraction analysis, it is shown that the mechanical activation reduces the grain size and makes the grains more defective. According to the data of electrochemical impedance spectroscopy, the ionic conductivity of the system KNO 3 –Al 2 O 3 obtained by mechanical activation is 3.8 × 10 –5 S/cm at T = 373 К and 2 × 10 –3 S/cm at T = 473 К and its activation energy is 0.19 eV, which is comparable with the parameters of composites with the same chemical composition obtained by the ceramic method. The Raman spectroscopic study reveals the formation of the metastable γ-KNO 3 phase in the system KNO 3 –Al 2 O 3 at the temperature above 397 К . The increase in conductivity of the KNO 3 –Al 2 O 3 composite at 373–403 К is associated with the presence of an additional metastable γ-KNO 3 phase.

In this paper, the effect of mechanical activation on the structure and electrical conductivity of the KNO3-Al2O3 composite was studied. Based on the analysis of DSC curves measured during heating and cooling of the sample, it was found that the enthalpy of phase transitions decreases with increasing time of mechanical activation of the 0.5KNO3-0.5Al2O3 composite. X-ray diffraction analysis shows that mechanical activation leads to a decrease in the grain dimension and an increase in the defectiveness. Based on the electrochemical impedance spectroscopy data, it was determined that for the KNO3-Al2O3 system subjected to mechanical activation, the values of specific ionic conductivity are 3.8×10-5 S/cm at T = 373 K and 2×10-3 S/cm at T = 473 K and the energy value activations of 0.19 eV are comparable with the parameters of a composite of the same chemical composition obtained by the ceramic technique. Raman spectroscopy revealed the formation of a metastable γ-phase KNO3during the mechanoactivation of the composite, which is stable at temperatures above 397 K. It is proposed that an increase in electrical conductivity in the KNO3-Al2O3 composite at 373-403 K is due to the presence in the composite of an additional metastable γ-phase KNO3.

This paper presents the results of a differential scanning calorimetry study of phase transitions in (1 − x)MNO3–xAl2O3 (M = Li, Na, K, Rb) composites. It was found that an additional stable high-temperature ferroelectric phase of potassium nitrate (phase III) is formed in KNO3–Al2O3 nanocomposites. Sharp decrease in enthalpies of phase transitions of salts, including melting enthalpies, was observed in the nitrates doped with Al2O3 nanoparticles. For the first time, the concept of the specific enthalpy of phase transitions of a salt in a composite is introduced, which is normalized to the salt concentration and specific surface area of the oxide and depends only on the nature of the contacting substances. The regularities of the change in the enthalpy of melting of (1 − x)MNO3–xAl2O3 versus the radius of alkali metal cation have been established.

The paper presents a comprehensive study of the Li0.42K0.58NO3- R (R = alpha-Al2O3, gamma-Al2O3, SiO2) and (LiNO3 - LiClO4) - gamma- 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-gamma-Al(2)O(3 )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 v1 (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. (C) 2021 Elsevier B.V. All rights reserved.

The thermal effects and dielectric properties of a lithium-ion polymer electrolyte, namely, polyethylene glycol (PEG 1500)–lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), are studied for different molar fractions of salt in polymer by the methods of electrochemical impedance spectroscopy and differential thermal analysis. The complicated form of the “final” diffusion impedance of the PEG 1500‑LiTFSI electrolyte system may be associated with superposition of two processes that occur simultaneously in the solid electrolyte interphase (SEI) layer and at the boundary of the electric double layer (EDL) It is found that the obtained diffusion coefficients do not fit the Arrhenius model in describing the mechanism of transfer of lithium ions in the PEG polymer matrix. It is shown that as the concentration of LiTFSI in PEG 1500 increases, the time of dielectric relaxation decreases. It is assumed that in the PEG 1500–LiTFSI system, the increase in the ionic conductivity with the increase in the temperature up to 343 K proceeds due to wave fluctuations of the lithium ion and the movements of the PEG 1500 matrix.

The reasons leading to the asymmetry of the shape of the ν1(А1) contour of the nitrate ion in the spectra of lithium nitrate melts were analyzed. It was shown that the application of the Rothschild–Yao theory gives the best agreement between the calculated and experimental spectra. However, the physical meaning of some of parameters given in this theory is not clear. The asymmetry of shape of the vibration contour ν1(A1) of the nitrate ion for a lithium nitrate melt, can be caused by the inhomogeneity of local structure caused by different rates of dynamic interactions between the particles of system.

The reasons leading to asymmetry of shape of ν1 (A1) contour of nitrate ion in Raman spectra of lithium nitrate melts are discussed. It is shown that the application of Rothschild - Yao theory gives best agreement between the calculated and experimental spectra. However, physical meaning of some of parameters given in this theory is not clear. For lithium nitrate melt, asymmetry of the shape of vibration contour ν1 (A1) of the nitrate ion can be caused by the inhomogeneity of local structure due to different rates of dynamic interactions between particles of the system.

A comprehensive study of lithium-conducting polymer electrolytes based on polyethylene glycol 1500 and lithium salts (LiSCN and LiN(CF3SO2)2) was carried out using thermogravimetry, differential thermal analysis, electrometry, and vibrational spectroscopy. Their phase composition was refined, structural changes resulting from varying the concentration of lithium salts were determined, the most probable structures of complex solvate and ionic complexes were established.

Vibrational spectroscopy and X-ray diffraction are used to study phase compositions and structural properties of composite systems (composites) based on the LiNO 3 -KNO 3 eutectic binary system with the addition of alumina nanopowder. High nanopowder concentrations are shown to cause amorphization of the salt system.

Vibrational spectroscopy and X-ray diffraction are used to study phase compositions and structural properties of composite systems (composites) based on the LiNO3-KNO3 eutectic binary system with the addition of alumina nanopowder. High nanopowder concentrations are shown to cause amorphization of the salt system.

Composite solid electrolytes are synthesized on the basis of the eutectic nitrate mixture of 0.42LiNO3–0.58KNO3 doped by aluminum oxide nanosized powder. The impedance spectroscopy technique is used to study the conductivity of the obtained composites. Heterogeneous doping results in an increase in ion conductivity and a decrease in activation energy. The method of Raman spectroscopy shows that the doping by aluminum oxide leads to formation of an amorphous phase. At low nanopowder concentrations, amorphization is brought about by the lithium nitrate phase.

Методами колебательной спектроскопии и рентгеновской дифракции исследован фазовый состав и структурные свойства композиционной системы (композитов) на основе эвтектической бинарной системы LiNO3—KNO3 с добавками наноразмерного порошка оксида алюминия. Показано, что при больших концентрациях нанопорошка происходит аморфизация солевой системы.

Temperature and phase dependences of Raman spectra (RS) and molecular relaxation characteristics of nitrate-ion vibrations in (1 – x)RbNO3 + xAl2O3 composites with various concentrations of Al2O3 nanopowder were studied. It was shown that the ν 1(A) vibrational relaxation time with filler concentration x = 0.6 was essentially constant in high-temperature phase RbNO3-II as compared with RbNO3-III, which indicated that the cubic RbNO3-III phase was stabilized. The salt subsystem was highly disordered at high filler concentrations so that structurally distinct states were difficult to detect at the macro level.

Методом рентгеновской дифракции исследованы фазовый состав и структурные свойства нитрата калия KNO3 и его гетерогенных композитов с наноразмерным порошком оксида алюминия Al2O3 при различных концентрациях нанопорошка Al2O3. Установлено, что в композитах (1+x)KNO3+xAl2O3 образуется дополнительная, высокотемпературная, ромбоэдрическая фаза нитрата калия (фаза III) с параметрами решетки a=5.4644 Angstrem, c=9.0842 Angstrem. Обнаружено, что с увеличением концентрации нанопорошка Al2O3 содержание основной фазы нитрата калия (фаза II) значительно уменьшается, при этом растет относительная доля фазы III в общем содержании нитрата в составе композита. Сделано предположение о "замораживании" данной фазы в нанокомпозите на межфазной границе раздела KNO3-Al2O3. Оценочный размер кристаллитов KNO3 в фазе III составил более 20 nm. Работа выполнена на оборудовании Аналитического центра коллективного пользования ДагНЦ РАН.

The phase composition and the structural properties of potassium nitrate KNO 3 and its heterogeneous composites with nanometer-sized powder of aluminum oxide Al 2 O 3 have been studied by X-ray diffraction at various concentrations of an Al 2 O 3 nanopowder. It is found that, in the (1– x )KNO 3 + x Al 2 O 3 nanocomposites, additional high-temperature rhombohedral phase of potassium nitrate (phase III) with lattice parameters a = 5.4644 Å and c = 9.0842 Å. With increasing concentration of Al 2 O 3 nanopowder, the content of the main potassium nitrate phase (phase II) is found to significantly decrease, and the relative fraction of the phase III in the total content of the nitrate in the composite composition increases. This phase is assumed to be “frozen” in the nanocomposite at the KNO 3 –Al 2 O 3 interface. The estimated size of KNO 3 crystallites in the phase III is more than 20 nm.