Temperature X-ray Diffractometry Research Articles

Experimental study and thermochemical assessment of the reciprocal system Li+, K+//Cl−, CO32−

In this work a new thermodynamic dataset of the reciprocal system Li+, K+//Cl−, CO32− was generated by using Calphad method with FactSage. After collecting and analyzing the available thermodynamic data in the literature, experiments were designed to improve the comprehensiveness of the new database. Specifically, Differential Thermal Analysis (DTA) was used (1) to confirm the eutectic temperature of the K2CO3–KCl system, (2) to check the solid solubility in the K2CO3–Li2CO3 system and (3) to measure the phase equilibria of the diagonal sections (i.e. Li2CO3–(KCl)2 and K2CO3–(LiCl)2) in the reciprocal system. In addition, the heat capacity of the intermediate compound LiKCO3 was measured by three types of Differential Scanning Calorimetry (DSC) and its phase transformation was studied by High temperature X-ray Diffractometry (HTXRD). Based on the literature data and the present experimental results, the thermodynamic data on pure LiCl, all sub-binary systems and the reciprocal system were reassessed in the new database, which can be used to calculate and predict the thermodynamic properties of the salt mixtures in the reciprocal system Li+, K+//Cl−, CO32− more precisely and reliably.

The mechanism of enhanced ionic conductivity in Li1.3Al0.3Ti1.7(PO4)3–(0.75Li2O·0.25B2O3) composites

Abstract The oxide-based Li+ conductors are considered as potential solid electrolytes for lithium-ion batteries. Among the NASICON–type materials, Li1.3Al0.3Ti1.7(PO4)3 (LATP) seems to be a promising candidate for application. Although its bulk conductivity is of the order of 10−3 S · cm−1, and seems to be sufficient for practical use, the total conductivity is considerably limited by the highly resistant grain boundaries. This shortcoming may be overcome by the formation of LATP–based ceramics with appropriate sintering aids. In this study, the 0.75Li2O·0.25B2O3 (LBO) glass with low melting point was chosen to improve the ionic conductivity of LATP. The properties of Li1.3Al0.3Ti1.7(PO4)3–y (0.75Li2O·0.25B2O3) (0 ≤ y ≤ 0.3) system were studied by means of: high temperature X-ray diffractometry (HTXRD), 6Li/7Li, 11B, 27Al and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), thermogravimetry (TG), scanning electron microscopy (SEM), impedance spectroscopy (IS) and density methods. Based on the experimental results, it is shown that the use of LBO glass as a sintering aid results in the enhancement of the total ionic conductivity of LATP ceramics. The correlations between apparent density, microstructure, composition, sintering temperature and ionic conductivity are presented and discussed. The presumed mechanism of the conductivity enhancement is analyzed in terms of the brick-layer model (BLM). The highest value of the total ionic conductivity, equal to 1.9 × 10−4 S · cm−1, was obtained for LATP–0.1LBO sintered at 800 °C.

Advanced technology for in-line continuous heat soak test of tempered sheet glass to guarantee high reliability

Advanced heat soak test (HST) technology, the ‘in-line continuous HST’ has been reported on the basis of experimental investigations and the T-T-T (time–temperature–transformation) relationship. The new HST technology is continuously carried out just after tempering (and heat strengthening) process. It was registered in ISO-20657 (2017). High temperature microscopy observations, high temperature x-ray diffractometry, differential thermal analysis, and micro-Raman spectrometry have been carried out in order to elucidate the α–β phase transformation of nickel sulphide in detail. The breakage ratio of in-line continuous HST is the same as that of conventional off-line HST or excellent. The ‘in-line continuous HST’ is already operating in a Japanese glass plant in order to produce tempered (and heat strengthened) sheet glass with high safety and reliability. The in-line continuous HST technology has the following benefits: (a) improvements of both productivity and reliability, (b) automatic inspection just after the tempering–quenching process, and (c) improvements to productive performance (many kinds products, heteromorphic products, and mass production). In this technical report, the advanced ‘in-line continuous HST’ technology which was standardised by several experimental investigations and analytical results will be shown in detail. The effective and efficient manufacturing technology of the tempered (and heat strengthened) sheet glass will be introduced.

Impact of Li2.9B0.9S0.1O3.1 glass additive on the structure and electrical properties of the LATP-based ceramics

The existing solid electrolytes for lithium ion batteries suffer from low total ionic conductivity, which restricts its usefulness for the lithium-ion battery technology. Among them, the NASICON-based materials, such as Li1.3Al0.3Ti1.7(PO4)3 (LATP) exhibit low total ionic conductivity due to highly resistant grain boundary phase. One of the possible approaches to efficiently enhance their total ionic conductivity is the formation of a composite material. Herein, the Li2.9B0.9S0.1O3.1 glass, called LBSO hereafter, was chosen as an additive material to improve the ionic properties of the ceramic Li1.3Al0.3Ti1.7(PO4)3 base material. The properties of this Li1.3Al0.3Ti1.7(PO4)3–xLi2.9B0.9S0.1O3.1 (0 ≤ x ≤ 0.3) system have been studied by means of high temperature X-ray diffractometry (HTXRD), 7Li, 11B, 27Al and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), thermogravimetry (TG), scanning electron microscopy (SEM), impedance spectroscopy (IS) and density methods. We show here that the introduction of the foreign LBSO phase enhances their electric properties. This study reveals several interesting correlations between the apparent density, the microstructure, the composition, the sintering temperature and the ionic conductivity. Moreover, the electrical properties of the composites will be discussed in the terms of the brick-layer model (BLM). The highest value of σtot = 1.5 × 10−4 S cm−1 has been obtained for LATP–0.1LBSO material sintered at 800 °C.

Characterization of Phosphate Buffered Saline (PBS) in Frozen State and after Freeze-Drying.

To study the effect of mannitol or trehalose on the crystallization behavior of solutes in phosphate buffered saline (PBS) when the solutions were frozen and freeze-dried. PBS (pH7.5 at RT) either alone, or with trehalose (5% w/v) or mannitol (1% w/v), were frozen and characterized using low temperature differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and pH measurement. Freeze dried lyophiles were characterized by XRD. In the absence of cosolutes, upon freezing PBS, a pH shift of ~ 4units was observed due to crystallization of Na2HPO4•12H2O. XRD indicated sequential crystallization of Na2HPO4•12H2O, NaCl•2H2O and KCl during cooling. When the frozen solutions were heated, two eutectics were observed - the first at ~ -24°C (ternary, NaCl•2H2O-KCl-ice) and the second at ~ -22°C (binary, NaCl•2H2O-ice). Trehalose completely inhibited buffer salt crystallization, whereas mannitol suppressed it partially thereby attenuating the magnitude of pH shift. The two eutectic meltings were also suppressed by the cosolutes. XRD of final lyophiles from PBS alone revealed peaks of anhydrous Na2HPO4, NaCl, and KCl. Trehalose rendered the lyophiles completely XRD amorphous, whereas in presence of mannitol, all the solutes except KH2PO4 crystallized. Freezing of PBS solution caused a pronounced pH shift due to selective crystallization of Na2HPO4•12H2O. The addition of trehalose or mannitol suppressed the buffer salt crystallization and attenuated the magnitude of pH shift. The potential instability of biologics due to pH shift in PBS, can be potentially mitigated with the cosolutes.

Role of the Strength of Drug-Polymer Interactions on the Molecular Mobility and Crystallization Inhibition in Ketoconazole Solid Dispersions.

The effects of specific drug-polymer interactions (ionic or hydrogen-bonding) on the molecular mobility of model amorphous solid dispersions (ASDs) were investigated. ASDs of ketoconazole (KTZ), a weakly basic drug, with each of poly(acrylic acid) (PAA), poly(2-hydroxyethyl methacrylate) (PHEMA), and polyvinylpyrrolidone (PVP) were prepared. Drug-polymer interactions in the ASDs were evaluated by infrared and solid-state NMR, the molecular mobility quantified by dielectric spectroscopy, and crystallization onset monitored by differential scanning calorimetry (DSC) and variable temperature X-ray diffractometry (VTXRD). KTZ likely exhibited ionic interactions with PAA, hydrogen-bonding with PHEMA, and weaker dipole-dipole interactions with PVP. On the basis of dielectric spectroscopy, the α-relaxation times of the ASDs followed the order: PAA > PHEMA > PVP. In addition, the presence of ionic interactions also translated to a dramatic and disproportionate decrease in mobility as a function of polymer concentration. On the basis of both DSC and VTXRD, an increase in strength of interaction translated to higher crystallization onset temperature and a decrease in extent of crystallization. Stronger drug-polymer interactions, by reducing the molecular mobility, can potentially delay the crystallization onset temperature as well as crystallization extent.

Characterization of CoQ 10-lauric acid eutectic system

Solid state characterization of coenzyme Q10 (CoQ 10) was carried out using differential scanning calorimetry (DSC), variable temperature X-ray diffractometry (VT-XRD) and hot/cold stage microscopy (H/CSM). It revealed that CoQ 10 exists in two polymorphic forms. The recrystallized samples of CoQ 10 melted at different temperatures either due to the wide crystal size variation or change in crystallinity. Further, the binary mixture of CoQ 10 and lauric acid (LA) formed eutectic mixture in the ratio 70:30 melting at 37.93°C, which was close to the predicted eutectic composition of 87.7:12.3 melting at 38.98°C. The values of actual liquidus temperatures for CoQ 10 are higher than the predicted liquidus temperatures. The experimental heat of fusion at eutectic point was less than the calculated heat of fusion. Activity coefficient of CoQ 10 in the binary mixture was less than unity, which indicates the attraction between the components of eutectic mixture.

Strength Characteristics of Resorbable Osteoconductive Ceramics Based on Diphosphates of Calcium and Alkali Metals

3 An investigation into the strength characteristics of ceramics based on diphosphates Ca(3-x)�F 2x(PO4)2 (x = 0-1 andF = Na, K) provides evidence of composition strengthening in the range х = 0.6-0.8 containing the greatest amount of the supercooled high-temperature modification α-�KZFJH 4. The method of high- temperature x-ray diffractometry is used to examine thermal expansion of rhenanite phases ofKZFJH 4.

Controlling the physical form of mannitol in freeze-dried systems

A potential drawback with the use of mannitol as a bulking agent is its existence as mannitol hemihydrate (MHH; C6H14O6·0.5H2O) in the lyophile. Once formed during freeze-drying, MHH dehydration may require secondary drying under aggressive conditions which can be detrimental to the stability of thermolabile components. If MHH is retained in the lyophile, the water released by MHH dehydration during storage has the potential to cause product instability. We systematically identified the conditions under which anhydrous mannitol and MHH crystallized in frozen systems with the goal of preventing MHH formation during freeze-drying. When mannitol solutions were cooled, the temperature of solute crystallization was the determinant of the physical form of mannitol. Based on low temperature X-ray diffractometry (using both laboratory and synchrotron sources), MHH formation was observed when solute crystallization occurred at temperatures⩽−20°C, while anhydrous mannitol crystallized at temperatures⩾−10°C. The transition temperature (anhydrate – MHH) appears to be ∼−15°C. The use of a freeze-dryer with controlled ice nucleation technology enabled anhydrous mannitol crystallization at ∼−5°C. Thus, ice crystallization followed by annealing at temperatures⩾−10°C can be an effective strategy to prevent MHH formation.

Accelerating disorder–order transitions of FePt by preforming a metastable AgPt phase

Many approaches had been reported to successfully reduce the transition temperature of FePt from A1 to L10 phase, though without detailed knowledge. In this work, we deposited the metastable AgPt layer adjacent to the Fe layer and addressed the importance of vacancies in the disorder–order transition of FePt at reduced temperatures on the basis of a kinetic diffusion model. The decomposition of the metastable AgPt phase, creating excess vacancies during the post-deposition annealing process, accelerated the intermixing between Fe and Pt and the nucleation of L10 FePt. The evolution of phase transformation from AgPt–Fe to L10 FePt–Ag was monitored by in situ high temperature X-ray diffractometry and was also validated by first-principles calculations. The intermixing between Fe and Pt and the nucleation of L10 FePt after annealing at 230°C were directly observed by transmission electron microscopy and grazing incidence X-ray diffractometry, respectively. With the assistance of the decomposition of AgPt, we obtained a (001)-dominated L10 FePt film with an out-of-plane coercivity as large as 13.3 kOe after annealing at a temperature as low as 350°C. The principles of the proposed method can be applied for versatile disorder–order phase transitions.

In-situ determination of austenite and martensite formation in 13Cr6Ni2Mo supermartensitic stainless steel

Abstract In-situ analysis of the phase transformations in a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) was carried out using a thermo-magnetic technique, dilatometry and high temperature X-ray diffractometry (HT-XRD). A combination of the results obtained by the three applied techniques gives a valuable insight in the phase transformations during the austenitization treatment, including subsequent cooling, of the 13Cr6Ni2Mo supermartensitic stainless steel, where the magnetic technique offers a high accuracy in monitoring the austenite fraction. It was found by dilatometry that the austenite formation during heating takes place in two stages, most likely caused by partitioning of Ni into austenite. The in-situ evolution of the austenite fraction is monitored by high-temperature XRD and dilatometry. The progress of martensite formation during cooling was described with a Koistinen–Marburger relation for the results obtained from the magnetic and dilatometer experiments. Enhanced martensite formation at the sample surface was detected by X-ray diffraction, which is assumed to be due to relaxation of transformation stresses at the sample surface. Due to the high alloy content and high thermodynamic stability of austenite at room temperature, 4 vol.% of austenite was found to be stable at room temperature after the austenitization treatment.

Role of Thermal Vacancies on Temperature Dependence of Lattice Parameter and Elastic Moduli in B2-type FeAl

ABSTRACTTemperature dependence of the lattice parameter and elastic moduli in Fe-40 and -43Al (at.%) was investigated by high temperature X-ray diffractometry (XRD) and the Electro-Magnetic Acoustic Resonance (EMAR) method. The thermal vacancy concentration was estimated from the activation enthalpy and entropy data of vacancy formation previously reported for FeAl. It was found that both the lattice parameter and the elastic moduli of FeAl have a linear relationship with temperature even in the temperature range where thermal vacancy concentration rapidly increases (above 400 °C), thus suggesting that newly generated thermal vacancies at elevated temperature do not make significant influence on the lattice parameter and the elastic properties of B2-type FeAl.

Mechanism on Heterogeneous Nucleation of the Primary Al Phase on TiAl<sub>3</sub> of a Hot-Dip Zn-11%Al-3%Mg-0.2%Si Coating on Steel Sheet

The solidification structure of a hot-dip Zn-11%Al-3%Mg-0.2%Si coating with a Ti addition on a steel substrate was investigated. Steel sheet was coated using a laboratory hot-dip galvanizing simulator. The coating was subsequently characterized via optical and high resolution scanning electron microscopy with EBSD and high temperature X-ray diffractometry. The hot-dip coating consisted of a combination of a Zn/Al/MgZn2 ternary eutectic structure, primary Al phase and MgZn2 phase. TiAl3 acts as a heterogeneous nucleation site for Al, which was shown to have perfect lattice coherency with TiAl3 as epitaxial Al growth from the TiAl3 was found. The growth direction of Al is along <110> and has a random texture, whereas Zn has a rather strong ND//<0001> fiber texture.

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La2NiO4+δ

Crystal structure and mechanical properties of La2NiO4+d were measured by high temperature X-ray diffractometry and in-situ small punch test as a function of temperature and oxygen partial pressure. As P(O2) increases, the lattice parameter perpendicular to the perovskite layer increases and that parallel to the layer slightly decreases, and the lattice volume slightly increases. Apparent and true thermal expansion coefficients were calculated from the variation of the lattice constants. The elastic modulus and the fracture strength become larger at higher P(O2) condition. This may be caused by the structural change due to excess oxygen.

Thermal expansion studies on UMoO 5, UMoO 6, Na 2U(MoO 4) 3 and Na 4U(MoO 4) 4

In the present work, thermal expansion behavior of lower valent sodium uranium molybdates, i.e., Na 2U(MoO 4) 3 and Na 4U(MoO 4) 4 were studied under vacuum in the temperature range of 298–873 K using high temperature X-ray diffractometry (HTXRD). Expansion behaviors of UMoO 5 and UMoO 6 were also studied in vacuum from 298 to 873 K and 773 K, respectively. UMoO 5 was synthesized by reacting UO 2 with MoO 3 in equi-molar proportion in evacuated sealed quartz ampoule at 1173 K for 14 h. Na 2U(MoO 4) 3 and Na 4U(MoO 4) 4 were prepared by reacting UMoO 5 and MoO 3 with 1 and 2 moles of Na 2MoO 4, respectively, at 873 K in evacuated sealed quartz ampoule. XRD data of UMoO 5 and UMoO 6 were indexed on orthorhombic and monoclinic systems, respectively, whereas, the data of Na 2U(MoO 4) 3 and Na 4U(MoO 4) 4 were indexed on tetragonal system. The lattice parameters and cell volume of all the four compounds, fit into polynomial expression with respect to temperature, showed positive thermal expansion (PTE) up to 873 K.

Dilatometry and high temperature x-ray diffractometry study of LaCrO3 prepared using microwave heating

The phase transitions in the LaCrO3 were studied using bulk dilatometry and high temperature X-ray diffractometry from room temperature to 1050 and 1200°C, respectively. LaCrO3 was prepared at 500°C from oxalate precursor employing microwave heating technique. Bulk shrinkage measurements on LaCrO3 pellets were carried out using dilatometer designed and fabricated in our own laboratory. Dilatometric curves of LaCrO3 showed two peaks in ΔL/L vs. temperature curves in the range 200–400 and 800–1000°C, respectively. These phase transitions have been confirmed using high temperature X-ray diffractometry. The role of simple technique like bulk dilatometry in detecting and monitoring the polymorphic transformations in solids is discussed for lanthanum chromates.

Ageing behavior in the Cu–10 wt.%Al and Cu–10 wt.%Al–4 wt.%Ag alloys

In this work the ageing behavior in the Cu–10 wt.%Al and Cu–10 wt.%Al–4 wt.%Ag alloys was studied using microhardness measurements, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and in situ high temperature X-ray diffractometry (XRD). The results indicated that the presence of Ag disturbs the (α + γ 1) pearlitic formation in the Cu–10%Al, stabilize the martensitic phase and causes the reaction of the consumption of α phase to be the dominant process on ageing at the temperature and time ranges considered. This is due the dissolution of Cu atoms in the martensitic matrix which decreases the Al relative fraction, thus decreasing the ordering degree of the β ′ → β ′ 1 ordered martensite and making the consumption of α phase the dominant process. This process is intensified by the presence of Ag precipitates that will interfere in the Al diffusion process.

Phase Stability of 10mol%Sc2O3-1mol%CeO2-ZrO2 Ceramics

ABSTRACTScandia-doped zirconia is a very promising material for solid oxide fuel cells due to its high oxygen conductivity in the 700-850°C temperature range. 10 mol% Sc2O3 - 1 mol% CeO2 - ZrO2 ceramics were sintered at temperatures 1100-1600°C using different heating rates and dwell times. Ceramics sintered at temperatures higher 1300°C were found to exist in cubic phase at room temperature and exhibit slow phase transformation from cubic (c) to rhombohedral (beta) phase between 330 and 400°C. Analysis of c-β phase transition efficiency in the ceramics shows a strong correlation between the transition rate and sintering temperature. Kinetics of phase transitions were studied by high temperature X-ray diffractometry (HTXRD) and differential scanning calorimetry methods. The reversible c-β phase transition was found to have very wide hysteresis (45-70°C), which depends on sintering temperature and density. Coefficients of thermal expansion of c- and β-phases were calculated from temperature dependence of lattice parameters obtained by HTXRD in the temperature range of 25-800°C. Microstructural changes on the surface of the cubic phase due to c-β phase transition studied by SEM and AFM.

Hollow biomorphic Al2O3 fibers produced from sisal

Al2O3 fibers with a hollow morphology were produced by Al-vapor infiltration-reaction and subsequent oxidation from pyrolysed fibers of natural sisal. Following pyrolysis, the bio-fiber template was reacted with gaseous Al at 1,400 °C–1,600 °C in vacuum to form Al4C3. After an oxidation/sintering process at 1,550 °C, the biomorphic Al4C3 fibers were fully converted into Al2O3, maintaining the microstructural features of the native sisal. Phase and microstructural characterization during processing were evaluated by high temperature X-ray diffractometry and scanning electron microscopy, respectively. Thermo-analyses were performed in the Al4C3 samples in order to estimate the reactions and the weight change during the oxidation step.

Thermal Diffusivity and Phase Transition of Rare Earth Manganites

Thermal diffusivity of nonstoichiometric PrMnO3 and NdMnO3 phases were measured by laser flash method from room temperature to 1100 K, in addition to the data of electrical conductivity, thermal analysis and high temperature X-ray diffractometry to detect the phase transition. The thermal diffusivity curve varied with increasing temperature and showed a clear anomaly with a sudden dip at the phase transition temperature. The transition temperature decreases with oxygen nonstoichiometry in each phase.