Calorimetric investigations of NaNO3 and NaNO2 embedded into porous glasses

Rysiakiewicz-Pasek, E.; Komar, Jarosław; Ciżman, A.; Poprawski, R.

doi:10.1016/j.jnoncrysol.2009.07.035

Cited by 15 publications

(9 citation statements)

References 7 publications

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“…For NCM PG46 + NaNO 3 near T c the sharp growth of ε' at kHz range was observed also, but there was no salient anomaly in dielectric response. It is important to note that the values of T c for these NCM's are in good agreement with results of specific heat measurements at heating [11] and dielectric data confirm the smearing of PT at decreasing of pore diameter. To determine the T c for PG7 + NaNO 3 (Fig.…”

Section: Dielectric Datasupporting

confidence: 82%

“…As for the orientational PT it becomes diffuse and C p (T) maximum shifts to lower temperatures at pore size decreasing [11]. Dielectric measurements of NaNO 3 within porous glasses with average pore diameter of 12 nm have shown that dielectric spectra are dominated by conductivity, but also weak dielectric dispersion is observed [12] and relaxation time τ decreases sharply approaching T c .…”

Section: Introductionmentioning

confidence: 99%

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Phase transitions and macroscopic properties of NaNO3 embedded into porous glasses

Rysiakiewicz-Pasek

Набережнов

Seregin

et al. 2011

Journal of Non-Crystalline Solids

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Section: Dielectric Datasupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Phase transitions and macroscopic properties of NaNO3 embedded into porous glasses

Rysiakiewicz-Pasek

Набережнов

Seregin

et al. 2011

Journal of Non-Crystalline Solids

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“…If gases and liquids tend to enter the pores spontaneously, the substances that are solid at normal conditions need to be either melted or dissolved to penetrate a porous matrix. The melt route has been applied to study the solid–solid transitions in sodium nitrite, − sodium nitrate, and potassium dihydrogen phosphate . The solution route has not been as common but has been utilized to examine the melting and solid–solid transition in sodium nitrate.…”

Section: Introductionmentioning

confidence: 99%

High Temperature Solid–Solid Transition in Ammonium Chloride Confined to Nanopores

2013

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This paper describes a calorimetric (DSC) study of the high temperature (∼190 °C) solid−solid phase transition in ammonium chloride in silica nanopores (4− 30 nm) and in bulk. The study focuses on the values of the transition heat and temperature as well as on the transition kinetics. Because ammonium chloride is loaded from a solution, the pores are only filled partially. Thermogravimetric analysis is employed to evaluate the pore fullness, which is further used to estimate the height of ammonium chloride layer deposited inside the pores. With increasing the layer height, the heat of transition increases toward the bulk value. Relative to the bulk value, the transition temperature measured on heating and on cooling respectively increases and decreases with decreasing the layer height. In larger pores (15 and 30 nm), the transition has revealed a second DSC peak that appears above 210 °C on heating and below 100 °C on cooling. The temperature dependencies of the effective activation energy derived from isoconversional kinetic analysis of DSC data have been parametrized in terms of the Turnbull−Fisher model. It is found that the transition in the pores encounters a larger free energy barrier to nucleation.

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“…Отметим также, что величина температурного гистерезиса в поведении η(T ) в данных нанокомпозитах составляет около 15−20 K. Ранее значительное увеличение температурного гистерезиса при фазовом переходе в NaNO 2 в условиях ограниченной геометрии было обнаружено для НКМ, в которых в качестве пористых матриц были использованы искусственные опалы [4,6] и пористые стекла [29] со средним диаметром пор 46 nm, величины гистерезиса в которых составляли порядка 10 К.…”

Section: Bulkunclassified

Эффекты, Связанные С Ограниченной Геометрией, В Нанокомпозитах На Основе Мезопористых Матриц 2d-Sba-15 И 3d-Sba-15, Содержащих Наночастицы Нитрита Натрия

Набережнов¹,

Стукова²,

Алексеева³

et al. 2019

Журнал Технической Физики

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The temperature dependences of the ferroelectric order parameter for nanostructured sodium nitrite on heating and cooling have been obtained from the analysis of the temperature evolution of diffraction spectra of neutron scattering on nanocomposites, produced by embedding of sodium nitrite into the pores of the mesoporous matrices 2D-SBA-15 (average pore diameter 69 (4) Å) and 3D-SBA-15 (average pore diameter 94 (5) Å ). It is shown that on heating the phase transition from the ferroelectric phase to the paraelectric one occurs at TC = 433 ± 1 K for both nanocomposite materials. The sizes of nanoparticles in both nanocomposites are determined and it is established that their size decreases on heating at approaching to the ferroelectric phase transition temperature. Temperature hysteresis (~ 15–20 K) have been found in the temperature dependence of the order parameter between heating and cooling regimes.

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Calorimetric investigations of NaNO3 and NaNO2 embedded into porous glasses

Cited by 15 publications

References 7 publications

Phase transitions and macroscopic properties of NaNO3 embedded into porous glasses

Phase transitions and macroscopic properties of NaNO3 embedded into porous glasses

High Temperature Solid–Solid Transition in Ammonium Chloride Confined to Nanopores

Эффекты, Связанные С Ограниченной Геометрией, В Нанокомпозитах На Основе Мезопористых Матриц 2d-Sba-15 И 3d-Sba-15, Содержащих Наночастицы Нитрита Натрия

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