Phase Quantification Research Articles

Spectroscopic investigations of polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) multicomponent chalcogenides

Abstract The composition dependence of physical properties of chalcogenides has recently been studied for their phase change properties and energy conversion. In the present work, we report the structure, composition, optical and Raman spectroscopy results for bulk polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) samples. The phase quantification and composition have been studied by using XRD and EDX techniques. The alloy composition up to 5 at.% of indium resulted in crystallization of AgSbSe2, while further increase in In content favored the formation of another chalcopyrite AgInSe2 phase yielding the solid solutions for this alloy system. A decrease in band gap up to x = 5 followed by its increase with an increase in indium concentration has been observed. The variations in shape and position of characteristic Raman bands has been used for understanding the structural modifications of the network with the variation in indium content.

Correlative Energy-Dispersive X-Ray Spectroscopic Tomography and Atom Probe Tomography of the Phase Separation in an Alnico 8 Alloy.

Alnico alloys have long been used as strong permanent magnets because of their ferromagnetism and high coercivity. Understanding their structural details allows for better prediction of the resulting magnetic properties. However, quantitative three-dimensional characterization of the phase separation in these alloys is still challenged by the spatial quantification of nanoscale phases. Herein, we apply a dual tomography approach, where correlative scanning transmission electron microscopy (STEM) energy-dispersive X-ray spectroscopic (EDS) tomography and atom probe tomography (APT) are used to investigate the initial phase separation process of an alnico 8 alloy upon non-magnetic annealing. STEM-EDS tomography provides information on the morphology and volume fractions of Fe-Co-rich and Νi-Al-rich phases after spinodal decomposition in addition to quantitative information of the composition of a nanoscale volume. Subsequent analysis of a portion of the same specimen by APT offers quantitative chemical information of each phase at the sub-nanometer scale. Furthermore, APT reveals small, 2-4 nm Fe-rich α 1 phases that are nucleated in the Ni-rich α 2 matrix. From this information, we show that phase separation of the alnico 8 alloy consists of both spinodal decomposition and nucleation and growth processes. The complementary benefits and challenges associated with correlative STEM-EDS and APT are discussed.

Characterisation of Minerals and Ores: On the Complementary Nature of Select Techniques and Beyond

This overview is written as a tribute to my teacher, Professor Arun Kumar Biswas who introduced me to the discipline of minerals characterisation over three decades back. The focus of the paper is on complementary nature of techniques used for mineralogical characterisation of ores, minerals and, intermediate and final products generated during processing. The subject matter is essentially covered in two parts. In the first part, a general outlook is given based on the research summary dealing with a wide spectrum of materials and processes investigated. The potential and limitations of some commonly used tools/techniques are highlighted. In the second part, specific examples are presented under different themes covering phase identification, quantification of phases, heterogeneity in ores, occurrence of minor elements and their reactivity, mechanically activated solids, and lastly, structure-leachability correlations.

A phase quantification method based on EBSD data for a continuously cooled microalloyed steel

Mechanical properties of steels depend on the phase constitutions of the final microstructures which can be related to the processing parameters. Therefore, accurate quantification of different phases is necessary to investigate the relationships between processing parameters, final microstructures and mechanical properties. Point counting on micrographs observed by optical or scanning electron microscopy is widely used as a phase quantification method, and different phases are discriminated according to their morphological characteristics. However, it is difficult to differentiate some of the phase constituents with similar morphology. Differently, for EBSD based phase quantification methods, besides morphological characteristics, other parameters derived from the orientation information can also be used for discrimination. In this research, a phase quantification method based on EBSD data in the unit of grains was proposed to identify and quantify the complex phase constitutions of a microalloyed steel subjected to accelerated coolings. Characteristics of polygonal ferrite/quasi-polygonal ferrite, acicular ferrite and bainitic ferrite on grain averaged misorientation angles, aspect ratios, high angle grain boundary fractions and grain sizes were analysed and used to develop the identification criteria for each phase. Comparing the results obtained by this EBSD based method and point counting, it was found that this EBSD based method can provide accurate and reliable phase quantification results for microstructures with relatively slow cooling rates.

How to quantify the transition phase during golf swing performance: Torsional load affects low back complaints during the transition phase

ABSTRACTThe transition phase of a golf swing is considered to be a decisive instant required for a powerful swing. However, at the same time, the low back torsional loads during this phase can have a considerable effect on golf-related low back pain (LBP). Previous efforts to quantify the transition phase were hampered by problems with accuracy due to methodological limitations. In this study, vector-coding technique (VCT) method was proposed as a comprehensive methodology to quantify the precise transition phase and examine low back torsional load. Towards this end, transition phases were assessed using three different methods (VCT, lead hand speed and X-factor stretch) and compared; then, low back torsional load during the transition phase was examined. As a result, the importance of accurate transition phase quantification has been documented. The largest torsional loads were observed in healthy professional golfers (10.23 ± 1.69 N · kg−1), followed by professional golfers with a history of LBP (7.93 ± 1.79 N · kg−1), healthy amateur golfers (1.79 ± 1.05 N · kg−1) and amateur golfers with a history of LBP (0.99 ± 0.87 N · kg−1), which order was equal to that of the transition phase magnitudes of each group. These results indicate the relationship between the transition phase and LBP history and the dependency of the torsional load magnitude on the transition phase.

Study of the Precipitation of Secondary Phases in Duplex and Superduplex Stainless Steel

The aim of this work is to study the precipitation mechanism of the intermetallic phases present in duplex stainless steels (UNS S32205 and UNS S32750), as well as to find out the most suitable method for detecting and analyzing accurately these secondary phases, particularly Sigma-phase, Chi-phase, nitrides and carbides. The samples were characterized after a solution annealing at 1080oC followed by an isothermal treatment at 830oC from 1 min to 9 h, with the purpose of figuring out the mechanism of chi-phase nucleation and nitrides formation in relation with the sigma-phase. The study has two main objectives: 1) to find out the most suitable technique for the detection, identification and quantification of the secondary phases, obtaining the best results with the combination of field emission scanning electron microscopy (FESEM) and backscattered electron detector (BSE) in comparison with the optical microscopy (MO); 2) to study the influence of the chemical composition on the nucleation mechanism of the intermetallic phases. It has been concluded that molybdenum balance content in chi-phase related to sigma phase is close to two, consequently the kinetics of nucleation and growth of these phases is remarkably faster when this alloying element content in the steel is higher. Chromium nitrides and carbides were also observed to precipitate as a result of the heat treatments carried out to the specimen wherein chromium nitrides role is a favorable site for the nucleation of sigma and chi phases.

Significantly enhanced energy‐storage density in the strontium barium niobate‐based/titanate‐based glass‐ceramics

AbstractTwo‐step crystallization process was employed to improve microstructure and energy‐storage density of the strontium barium niobate‐based/titanate‐based glass‐ceramics. By using two‐step crystallization process, the optimum nucleation temperature was obtained to improve dielectric breakdown strength. Compared to the breakdown strength by one‐step crystallization process, the breakdown strength by two‐step crystallization process is increased about 1.89 times with the optimum nucleation temperature. Energy‐storage density of 7.73 ± 0.26 J/cm3 is significantly improved by two‐step crystallization process and is about 2.9 times of 2.63 ± 0.17 J/cm3 by one‐step crystallization process. This result is attributed to the homogeneous nucleation improving the microstructures of glass‐ceramics. Identification and quantification of crystalline phases by using Rietveld refinement reveals the difference of dielectric constants for one‐step and two‐step crystallization processes.

Al<sub>2</sub>O<sub>3</sub>-YAG Biphasic Composite Phase Determination Using Rietveld Method Measurements

TheAl2O3-YAG biphasic composite has been extensively studied since this system has important properties such as high resistance to corrosion and creep in harsh environments. This material system is potentially very attractive for high temperatures applications. In this work, the precursor powders of Al2O3 and Y2O3, were homogenized in planetary ball mill for 2h, dried in oven at 120oC for 48h, sieved and deagglomerated. It was performed a series of heat treatments over the powder for verification of the YAG phase formation, using1100, 1200, 1300°C and 1400 °C for 3.0 h time. The powders of the starting mixture after grinding and calcinations were characterized for phase quantification using the Rietveld method. The complete formation of the YAG phase in the composite was determined at1300°C after 3h.

Detection of Secondary Phases in UNS S32760 Superduplex Stainless Steel by Destructive and Non-destructive Techniques

Duplex stainless steels (DSS), with a microstructure of an approximately equal mixture of ferrite (α) and austenite (γ) phases, are susceptible to the formation of undesirable phases if manufacturing processes are not carefully controlled. In particular, sigma phase (σ) is a Cr- and Mo-rich intermetallic phase, formed generally when DSS are by the temperature range from 600 to 900 °C, even for very short time periods. The precipitation of this phase induces detrimental effects in mechanical and corrosion resistance properties in the material, and even a low volume percentage of σ phase can significantly affect these properties. The current paper presents the effect of thermal treatments on UNS S32760 superduplex stainless steel seamless tubes, applied in order to promote the precipitation of different σ phase percentages in a ferrite/austenite microstructure. The detection and quantification of the σ phase using non-destructive ultrasounds testing has been one of the most relevant events of this study that contributes to improving the correlation of the results obtained using destructive and non-destructive techniques for the quantification of undesirable phases in superduplex seamless tubes during the manufacturing process.

Methodology for Analysis of the Reactivity of Coal Fly Ash Using Selective Dissolution by Hydrofluoric Acid

The use of some additions as cement replacement has played an important role in the amount of clinker reduction. Due to its huge worldwide availability one of the most important and recognised replace agent is the fly ash, but is also estimated that only 30 to 40% of fly ash is used, although there are some challenges to be overcome, such as the reactive potential quantification. Chemical analysis is typically determined by the oxides content and does not take into account the vitreous and crystalline phase ratio. Therefore, this paper describes in detail one selective dissolution method, based in the hydrofluoric acid attack, to the quantification of the vitreous phase (reactive) and crystalline phases (not reactive). Fly ash from Portuguese Pego thermoelectric power plant was submitted to different attacks. To confirm the method and its effects, chemical and physical analysis were performed, such as STA, XRF, XRD with Rietveld refinement, SEM, EDS and laser diffraction granulometry. The results can be used to quantify the potential reactivity of this type of fly ash. The best results were achieved with 1% hydrofluoric acid attack during 6 hours.

Validated high performance thin layer chromatography method for simultaneous determination of quercetin and gallic acid in Leea indica

A sensitive and reliable high performance thin layer chromatography method has been developed for the simultaneous estimation of quercetin and gallic acid in Leea indica, Vitaceae. Ethyl acetate extract prepared from hydrolysed aqueous alcoholic extract (70%) was applied on silica gel G 60 F254 plate. The plate was developed using toluene-ethyl acetate-formic acid, 5:4:1 (v/v/v) as a mobile phase and detection and quantification were performed by densitometric scanning at 254nm. The system was found to give well resolved bands for quercetin (Rf 0.63) and gallic acid (Rf 0.45) from other constituents present in the extract of L. indica. The correlation coefficient was found to be 0.991 and 0.999 with relative standard deviation, 0.97–1.23% and 0.1–1.13% for quercetin and gallic acid respectively in the developed method. The accuracy of the method was confirmed by conducting recovery studies at different levels using the standard addition method. The average recovery of quercetin and gallic acid was found close to 99% suggesting the accurateness of the method. The proposed validated high performance thin layer chromatographic method offers a new, sensitive, specific and precise gauge for quantification of quercetin and gallic acid in L. indica.

Application of thin-layer chromatography image analysis technique in quantitative determination of sphingomyelin

A sensitive and convenient method for sphingomyelin determination was developed based on thinlayer chromatography (TLC) and image-processing analysis. The mobile phase composition, detection and quantification conditions were systematically investigated through several trials. The molybdenum blue reaction allowed specific detection of the phospholipid with a high sensitivity and a wide linear range. Digital images of TLC plate chromatograms were captured with flatbed scanner and converted into peak chromatograms using TLSee® software and quantitative analysis was conducted. The linearity, sensitivity, accuracy and precision of the system were evaluated. The limits of detection and quantification were 0.5 and 1.7 μg/spot, respectively. Separation of the mixture consisting of sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine was also carried out.

Mineralogical quantification of iron ore sinter

The mineralogy and microstructure of sinter play an important role in determining the physical and metallurgical properties of iron ore sinter. Characterisation of sinter phases is, therefore, a cost-effective and complementary tool to conventional physical and metallurgical testing of iron ore sinter in evaluating and predicting sinter quality. Over the years, CSIRO (Commonwealth Scientific and Industrial Research Organisation) has developed a scheme for characterising iron ore sinter which classifies primary sinter phases, such as un-reacted and partially reacted haematite, magnetite and remnant fluxes, and secondary phases including silico-ferrite of calcium and aluminium (SFCA), secondary haematite and magnetite, glass and larnite. Quantification of these phases has traditionally been carried out by manual point counting under a petrographic microscope. However, new technologies based on automated optical image analysis, quantitative X-ray diffraction and scanning electron microscopy are now available for evaluation. In this study, two sinter samples of varying chemistry were prepared and characterised using both point counting and automated optical image analysis. Quantification of sinter phases is a complementary tool for comparing the physical properties of sinter obtained from various sinter blends, and sinter phase quantification results can be used for comparing pot-grate sinter with different metallurgical properties.

Quantitative Estimation of Mullite in Alumina Based Porcelain Insulators Samples

Although porcelain insulators in power lines have been in use for decades, several undergo catastrophic failures while early in service. A study addressing the materials aspects has been conducted on alumina based porcelain insulators. Apart from their electro mechanical stability characteristics, material aspects like composition, phase and microstructure play a very important role in their performance. The qualitative phase analyses on the insulator samples give an idea about the different major and minor phases present. Attempts have already been made to estimate α alumina and α quartz content in porcelain body. Mullite is another important phase present in the porcelain body, which gets formed during firing of raw materials during insulator manufacture and which has not been estimated quantitatively. An attempt has been made here to assess the mullite content in the alumina based insulator samples by X-Ray diffraction quantitative analysis. Internal standard method of quantification has been adopted successfully for the analysis. This article describes the quantification of mullite phase by the internal standard method based on X-Ray diffraction principle.

Direct decomposition X-ray diffraction method for amorphous phase quantification and glassy phase determination in binary blends of siliceous fly ash and hydrated cement

A direct decomposition method of X-ray diffraction pattern associated with amorphous phases in a binary blend containing hydrated cement and siliceous fly ash is developed. The method relies on identifying patterns associated with individual components within the overall intensity pattern produced by the total amorphous phase. The intensity pattern associated with the total amorphous phase in a binary blend of siliceous fly ash and hydrated cement is obtained using the Pawley intensity refinement method. The features of the intensity patterns associated with the amorphous reaction products in hydrated cement and the glassy content of siliceous fly ash extracted by decomposition of the overall intensity pattern produced by the combined amorphous phase are shown to match the features obtained directly from the pure phases. The direct decomposition method allows for quantification of amorphous components, which can be applied to study the evolving phases in a hydrating binary system.

Evaluation of Deep Eutectic Solvent for the selective extraction of toluene and quinoline at T = 308.15 K and p = 1 bar

The current work reports the selective separation of aromatic and poly aromatic hydrocarbon (PAH) with Deep Eutectic Solvents (DES). The low cost DES are based on a mixture of a hydrogen bond donor and organic salt. The organic salt namely Methyltriphenylphosphonium bromide(MTBP) along with the hydrogen bond donor (HBD) were taken in a ratio of 1:4 to synthesize potential DES. DES were then varied based on the selection of two hydrogen bond donor namely ethylene glycol(DES1) and glycerol(DES2). In order to study their effectiveness, Liquid-liquid Equilibrium experiments were performed for the removal of toluene and quinoline respectively. LLE data corresponding to the ternary systems:[DES1(1) + Toluene(2) + Heptane(3)],[DES2(1) + Toluene(2) + Heptane(3)], [DES1(1) + Quinoline(2) + Heptane(3)] and [DES2(1) + Quinoline(2) + Heptane(3)] were generated at 308.15 K and atmospheric pressure. 1H NMR analysis were then used for the quantification of both extract and raffinate phases. Distribution coefficient (β) and selectivity (S) were subsequently obtained and it was found that toluene had a poor selectivity than quinoline. The cross contamination of DES and heptane across either phases were found to be nearly zero. Further the Non-random two liquid (NRTL) and UNiversal QUAsi Chemical (UNIQUAC) thermodynamic model were used to compare the experimental tie line data. This gave an excellent fit with a root mean square deviation (RMSD) values for both models ranging from (0.28–0.31%) and (0.22–0.73%) respectively. DES1, namely Methyltriphenylphosphonium bromide + ethylene glycol was thus recommended as a potential solvent for the separation of aromatic and PAH component.

High-temperature microstructural evolution and quantification for alloys IN740 and IN740H: comparative study

In ultra-supercritical power plants, Ni-base alloys are candidate materials for long-term, high-temperature applications, operating at temperatures and pressures as high as 750°C and 35 MPa. Alloy IN740 and its modification, alloy IN740H, are considered for such applications. Their microstructural evolution, at 750°C for times ranging between 3000 and 5000 hours, has been investigated by means of scanning electron microscopy, electron back-scattered diffraction, energy dispersive X-ray analysis and phase quantification. All phases were identified and quantified allowing comparison between the two microstructures, their evolution and stability. Particular attention was paid to γ′, η and G phases. The results are used within a broader investigation aimed at improving and further developing a predictive creep model based on continuous damage mechanics.

Quantification of Phase Evolution in Praseodymium Nickelates

A new method to quantify the phase evolution in nickelates is developed using sintered metal grids as cathode current collectors. The metal grids not only enable us to carry out phase quantification studies in cathodes, but also retaining the cell’s performance and stability. Moreover, they are chemically compatible with the cathode and allow XRD analysis of the surface and bulk of the cathode after cell operation. Multiple cells were tested to study the reproducibility of measurements. High performance was observed in cells with metal grids, extending the application of this method to cathode durability studies in state-of-the-art SOFCs. Respective advantages and challenges of the method are discussed with an emphasis on phase quantification, and the effects of different noble metals in cells regarding their thermal, electrical, chemical, and mechanical stability. Au was found to be the most suitable current collector due to its low chemical reactivity with the cathode and mechanical compatibility at operating conditions.

Simultaneous quantification of buprenorphine, naloxone and phase I and II metabolites in plasma and breastmilk by liquid chromatography–tandem mass spectrometry

Opioid abuse during pregnancy is associated with fetal growth restriction, placental abruption, preterm labor, fetal death, and Neonatal Abstinence Syndrome. Current guidelines for medication-assisted opioid addiction treatment during pregnancy are methadone or buprenorphine monotherapy. Buprenorphine/naloxone combination therapy (Suboxone®) has not been thoroughly evaluated during pregnancy and insufficient naloxone safety data exist. While methadone- and buprenorphine-treated mothers are encouraged to breastfeed, no studies to date investigated naloxone concentrations during breastfeeding following Suboxone administration. For this reason, we developed and fully validated a liquid chromatography–tandem mass spectrometry method for the simultaneous quantification of buprenorphine, buprenorphine–glucuronide, norbuprenorphine, norbuprenorphine-glucuronide, naloxone, naloxone-glucuronide and naloxone-N-oxide in 100μL human plasma and breastmilk in a single injection following protein precipitation and solid-phase extraction. Lowest limits of quantification were 0.1–2μg/L with 20–100μg/L upper limits of linearity. Bias and imprecision were <±16%. Matrix effects ranged from −57.9 to 11.2 and −84.6 to 29.3% in plasma and breastmilk, respectively. All analytes were stable (within ±20% change from baseline) under all tested conditions (24h room temperature, 72h at 4°C, 3 freeze/thaw cycles at −20°C, and in the autosampler for 72h at 4°C). For proof of concept, buprenorphine and its metabolites were successfully quantified in authentic positive maternal and infant plasma and paired breastmilk specimens. This comprehensive, highly sensitive and specific method detects multiple buprenorphine markers in a small specimen volume.

Identifying and quantifying amorphous and crystalline content in complex powdered samples: application to archaeological carbon blacks

Carbon black materials have been frequently used from prehistory as pigments for drawings and paintings and also as dyes, inks and cosmetics, since they are easy to make by burning organic matter. However, the carbonaceous phases they form are often ill-ordered and not easy to characterize. Five carbon black Roman micro samples found in vessels in houses in Pompeii were studied. These precious powders correspond to mixed phase samples that contain both crystalline and ill-ordered components. Here, a methodological approach that accomplishes the identification, quantification and mapping of the different phases in these heterogeneous samples using synchrotron-based techniques is proposed. The results were compared with those from scanning electron microscopy. Information about the nature of the mixtures and the origin of carbon black pigments is obtained. The use of charred vegetable materials is concluded, independently of the shape and the nature of the container.