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Abstract  

The eutectic binary phase diagrams of volatilizable energetic material 1,3,3-trinitroazetidine (TNAZ) with 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 1-methyl-2,4-dinitroimidazole (MDNI) have been investigated by high pressure differential scanning calorimeter (PDSC), respectively. The liquefying and melting processes of TNAZ/RDX and TNAZ/MDNI volatilizable systems have been studied. On the basis of the data of apparent fusion heat and liquefying temperature, the phase diagrams of apparent fusion heat (H) with composition (X) and liquefying temperature (T) with composition (X) were constructed, respectively. The results showed that the gasification or volatilization of easy volatile energetic materials could be efficiently restrained by high pressure atmosphere, and the perfect and ideal phase diagrams can be constructed. The eutectic temperatures for TNAZ/RDX and TNAZ/MDNI are measured to be 95.5 and 82.3 °C, respectively. The eutectic compositions of mole ratios for the two systems are obtained to be 93.55/6.45 (TX method), 93.79/6.21 (H–X method) and 62.25/37.75 (TX method), 63.29/33.71 (HX method), respectively.

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Abstract  

The thermotropic phase solid–solid transitions compound (n-CnH2n+1NH3)2ZnCl4 (n = 14, 16, 18) were studied, and a series of their mixtures were prepared. These laminar materials contain bilayers sandwiched between metal halide layers. The low temperature crystal structures of the pure salts are characteristic of the piling of sandwiches in which a two-dimensional macro-anion ZnCl4 2− is sandwiched between two alkylammonium layers. These layers become conformationally disordered in the high temperature phases. The subsolidus binary phase diagrams of (n-C14H29NH3)2ZnCl4-(n-C18H37NH3)2ZnCl4 and (n-C16H33NH3)2ZnCl4-(n-C18H37NH3)2ZnCl4 were established by differential thermal analysis and X-ray diffraction. In each phase diagram, an intermediate compound and two eutectoid invariants were observed. There are three noticeable solid solution ranges (α, β, γ) at the left boundary, right boundary, and middle of the phase diagram.

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Rubidium and lithium butanoates binary phase diagram

Formation of a stable lyotropic liquid crystal phase and two mixed salts

Journal of Thermal Analysis and Calorimetry
Authors: F. Martínez Casado, M. Ramos Riesco, and J. Cheda

Abstract  

The temperature and enthalpy vs. composition diagrams of the binary system [xC3H7CO2Li+(1–x)C3H7CO2Rb], where x=mole fraction, were determined by differential scanning calorimetry (DSC). This binary systems displays the formation of two mixed salts with a composition 1:1 and 1:2, which melt incongruently at T fus=590.5 K, with Δfus H m=11.6 kJ mol–1, and congruently at T fus=614.5 K, with Δfus H m=20.2 kJ mol–1, respectively. The phase diagram also presents an ionic liquid-crystalline phase in a wide temperature range: 95 K.

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Abstract  

In this work the effect of oxygen pressure on the primary crystallisation fields for REBa2Cu3O7-x(RE=Nd, Sm, and Eu) has been studied. A DTA apparatus has been modified in order to carry out analyses under gas pressure, so the trend of temperatures of peritectic decomposition of the REBa2Cu3O7-xphases and of the eutectic equilibrium involving REBa2Cu3O7-x phases and flux mixture "Ba2Cu5O7" have been studied at oxygen pressures of 0.21, 1, and 10 atm. This showed that primary crystallisation fields spread at the increase of the oxygen pressure and allowed us to calculate the enthalpies of reactions of REBa2Cu3O7-xphases too.

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Journal of Thermal Analysis and Calorimetry
Authors: Masoud Nazarian-Samani, Ali Reza Kamali, Mahboobeh Nazarian-Samani, Roohallah Mobarra, and Saber Naserifar

Introduction Ni–B binary phase diagram ( Fig. 1 ) [ 1 ] shows several intermetallics of NiB, m -Ni 4 B 3 , o -Ni 4 B 3 , Ni 2 B, and Ni 3 B, respectively. These intermetallics have found interesting applications such as

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Abstract  

Differential scanning calorimetry (DSC) was used to construct phase diagrams of binary mixtures of alkylcyclohexanes and to characterize metastable phases formed in the binary mixtures. The experimentally measured liquidus curves were compared to the liquidus curves calculated using ideal solution theory. The measured phase diagrams of pentadecylcyclohexane/nonadecylcyclohexane and octadecylcyclohexane/nonadecylcyclohexane binary mixtures are consistent with theoretical phase diagrams constructed based on the assumption that these mixtures form eutectic systems. It was also observed that a metastable phase formed in some binary mixtures of pentadecylcyclohexane/nonadecylcyclohexane under fast cooling conditions. It is hypothesized that this metastable phase recrystallizes into the eutectic phase upon heating.

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constructed by calculating from the data of the five T – X binary phase diagrams [ 11 – 13 ]. Experimental Materials The four energetic materials used in this study are 3,4-dinitrofurazanfuroxan (DNTF) 1

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Journal of Thermal Analysis and Calorimetry
Authors: S. Wacharine, D. Hellali, H. Zamali, J. Rogez, and M. Jemal

Abstract

The phase transitions of RbNO3 and the binary phase diagram of (Cs,Rb)NO3 were investigated at atmospheric pressure, using simultaneous direct and differential thermal analysis, μDTA and DSC techniques. A fourth phase transition of RbNO3 has been observed at temperature near the melting point. The phase diagram of this system is characterised by a eutectic, two eutectoid and an azeotropic-like invariants. Three limited solid solutions and two continuous solid solutions have been detected at low temperature.

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