Quantitative X-ray Powder Diffraction Analysis Research Articles

Material and mechanical properties of young basalt in drill cores from the oceanic island of Surtsey, Iceland

Characterization of 2017 drill core samples from Surtsey, an oceanic island produced by 1963−1967 eruptions in the offshore extension of Iceland’s east rift zone, reveals highly heterogeneous microstructural, physical, and mechanical properties in subaerial, submarine, and subseafloor basaltic deposits. The connected porosity varies from 42% in weakly consolidated lapilli tuff in a submarine inflow zone to 21% in strongly lithified lapilli tuff in upper subseafloor deposits near the explosively excavated conduit. Permeability, however, varies over six orders of magnitude, from 10−18 m2 to 10−13 m2. Uniaxial compressive strength, P-wave velocity, and thermal conductivity are also highly variable: 10−70 MPa, 1.48−3.74 km·s−1, and 0.472−0.862 W·m−1·K−1, respectively. Synchrotron X-ray microdiffraction analyses integrated with major-element geochemistry and quantitative X-ray powder diffraction analyses describe the initial alteration of fresh glass, incipient consolidation of a fine-ash matrix, and partial closure of pores with mineral cements. Permeability, micromechanical, and thermal property modeling highlight how porosity and pore size in eruptive fabrics—modified through diverse cementing microstructures—influence the physical properties of the pyroclastic deposits. Borehole temperatures, 25−141 °C (measured from 1980 to 2018), do not directly correlate with rock strength properties; rather, the abundance and consolidation of a binding fine-ash matrix appears to be a primary factor. Analytical results integrated with archival data from 1979 drill core samples provide reference parameters for geophysical and heat transfer studies, the physical characteristics of pyroclastic deposits that lithify on a decadal scale, and the stability and survival of oceanic islands over time.

Reduce the cost and embodied carbon of ultrahigh performance concrete using waste clay

Recent research has recognized limestone calcined clay cement (LC3) a promising sustainable cementitious material. While LC3 could be used in a wide range of applications, it is important to explore its feasibility in developing (ultra-)high performance concrete. In this paper we attempt to produce ultrahigh performance LC3 concrete (UHP-LC3). With 20%, 30%, and 40% OPC replaced by coal gangue waste calcined clay and limestone (LC2), the mechanical, hydration, and microstructural properties were extensively studied. The mechanical properties were investigated by compressive and flexural tensile tests. The hydration behavior of UHP-LC3 was evaluated by thermogravimetric analysis (TGA), quantitative X-ray powder diffraction (QXRD) analysis, 29Si nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscope (SEM). Finally, the microstructure of UHP-LC3 was studied by mercury intrusion porosimetry (MIP). Results show that the substitution of LC2 improve the early strength by quickly pozzolanic reaction to form denser hydration products as well as the synergistic interaction between silica fume and limestone/calcined clay in the system. However, the long-term strength would drop as LC3 caused insufficient hydration reaction due to the high water-demand of calcined clay that reduced the amount of free water. Also, there are abundant unreacted calcined clay particles in the hydrated system. Meanwhile, LC3 substitution of OPC seems to improve the polymerization of C-A-S-H gel and densify the pore structure, thus display excellent carbonation resistance. This paper explores new options to prepare more sustainable and cost-effective UHPC.

A comparable study on the deterioration of limestone powder blended cement under sodium sulfate and magnesium sulfate attack at a low temperature

The deterioration mechanisms and corrosion products of Portland cement blended with limestone powder (PLC) exposed to external sulfate solutions at 5 ± 1 °C were investigated in the present study. The damage degree of paste specimens was evaluated by the evolution of appearance, strength and volume. Furthermore, to identify and quantitatively analyse the compositions of corrosion products during sulfate attack, Fourier transform infrared spectroscopy, quantitative X-ray powder diffraction and electron microprobe analysis were applied in this study. The results showed that the PLC were seriously damaged after immersion for 360 days due to the expansion of volume and the loss of strength. Moreover, the type of sulfate solution had great influence on the compositions of corrosion products from PLC immersed in sulfate solutions at low temperatures. The corrosion products of PLC immersed in sodium sulfate solution were mainly composed of thaumasite and ettringite. However, in scenario of magnesium sulfate solution, the corrosion products were basically gypsum coupled with thaumasite. The analysis results indicated that the low pH value of pore solution and decalcification effect due to magnesium sulfate attack was probably beneficial for thaumasite formation by transformation of ettringite (woodfordite route), while the sodium sulfate seemed to favour the formation of thaumasite via direct route.

Analysis of the Kinetics of Devitrification and Crystallization of a Melilite Mold Powder Slag for Medium Carbon Steel Billet Casting

High-speed continuous casting of steel billets entails considerable turbulence in the liquid core, which results in significant slag entrapment unless high viscosity slags are used. It has been suggested that such slags remain glassy or crystallize slightly under the prevailing mold cooling, temperature and residence time conditions. Slags whose composition lead to formation of melilite minerals (i.e., to formation of calcium sodium magnesium aluminum iron disilicates), as the main crystalline phase, possess viscosities > 0.5 Pa/s at 1573 K (1300 °C), are low or do not contain F, and incorporate transition metal oxides (e.g., FeO, MnO and TiO) to absorb infrared radiation and soften steel shell-to-mold heat transfer. In this work, a commercial melilite mold powder, for casting medium carbon steels round billets, is selected to carry out detailed analysis of the kinetics of precipitation of crystalline phases from glassy—devitrification—and super-cooled liquid slags—crystallization—under non-isothermal and isothermal conditions. High-temperature confocal laser scanning microscopy is used in both cases and differential scanning calorimetry just in non-isothermal ones. Assessment of amorphous and crystalline phases in treated samples is done by quantitative X-ray powder diffraction analysis. It is found that even after prolonged treatment (» 36,000 seconds) at 1248 K (975 °C) approximately 13 wt pct of the slag remains amorphous. Additionally, the results indicate that nucleation of crystalline phases in super-cooled liquid and glassy slags occurs on the surface. Thus, it is found that crystallization kinetics is strongly influenced by the topography of the surface with which the super-cooled liquid is in contact, as well as, by shearing actions imposed on the liquid slag surface, which contribute by developing nucleation sites. Devitrification tends to be stronger on surfaces contacting foreign walls and over cracks. Moreover, it is found that predictions of the kinetic model, developed for estimating time–temperature–transformation diagrams from non-isothermal differential scanning calorimetry data, portray reasonably well experimental results of crystallization, as well as devitrification of consolidated samples.

Rheological properties of belite-rich cement doped with sulfur

Reactive belite cement based on clinker doped with sulfur is a new type of low-energy cement that is still in the laboratory testing phase. In terms of application, one of the desired properties of new cement is its well-defined rheological behavior in fresh state. The chemical composition of the belite cement was determined by wet chemistry analysis, the phase composition of the belite cement clinker by quantitative X-ray powder diffraction analysis and microscopic point counting and specific surface by Blaine method. Rheological properties were determined by rotational rheometer in flow and oscillation regime. Shear and time dependent rheological parameters were calculated from flow curves. Stability of belite cement paste was judged based on the critical strain determination in amplitude sweep test. Setting was evaluated by Tussenbrock needle penetration test and oscillation time test on rheometer. The properties of the laboratory belite cement were correlated to industrial cement CEM I, CEM II/A-LL and CEM III/A. Reactive belite cement pastes show good flow properties both due to small amount of alite and larger amount of rounded belite grains and clusters. Belite rich cement show decent stability comparable to CEM III and very good dispersing efficiency of PCE based HRWR.

X-ray powder diffraction analysis of a tungsten carbide-based ceramic

The results of the qualitative and quantitative X-ray powder diffraction analysis of the W–C system samples are presented. Powder samples were nanopowders of α-WC/W2C obtained by plasma chemical synthesis. High-density fine-grained structure of ceramics was formed using the method of electro pulse plasma sintering (spark plasma sintering) from the initial powder of the α-WC. The optimal experimental conditions for the X-ray diffraction proceeding of the tungsten carbide based ceramic samples were chosen according to the preliminary experiments. Reference intensity ratio method for quantitative phase analysis was used in this study.

Prediction and Measurement of the Kinetics of Isothermal Crystallization and Devitrification of Mold Powder Slags

The rate and extent of formation of crystalline phases in the slag film that develops between the mold and the strand in steel continuous casting determine heat transfer and lubrication between them and therefore play crucial roles in shell integrity. In this work, a commercial mold powder for casting medium carbon (MC) thin steel slabs is selected for carrying out detailed comparisons between predicted and experimental results of the rates of isothermal crystallization and devitrification of liquid and glassy slag, respectively. Predictions are obtained with a kinetic model that combines the induction period (of Simon and Kolman) and the Kissinger methods to evaluate time–temperature–transformation (TTT) diagrams for the devitrification and crystallization reactions associated with the peaks appearing in non-isothermal thermo-analysis traces. To obtain experimental validation of the diagram, a high-temperature confocal laser scanning microscope (HT-CLSM) is used to rapidly heat or cool a sample, ~ 140 mg, of glassy powder or liquid slag, respectively, to selected isothermal conditions, where it is held for a prescribed length of time before quenching. Identification and quantification of the phases present in the quenched samples are done by a quantitative X-ray powder diffraction analysis (QXRPDA) method that uses a PONKCS (partial or not known crystal structure) procedure based on Le Bail and Rietveld strategies for refinement of diffraction patterns. The many experimental results indicate that the predicted TTT diagrams for devitrification and crystallization of the mold slag give a good estimation of the rate of the transformations that take place at different temperatures and reveal the differences in the reactions that occur along both paths.

Sintering characteristics of BCSAF cement clinker with added wastes from production of manganese and magnesium metals

The production of belite-calcium sulfoaluminate-ferrite (BCSAF) cement with the addition of industrial wastes as feedstock has been studied for many years. The preparation of clinkers is essential in cement production, in which all raw materials react with each other to generate key phases in cement under some specified conditions. The objective of this study was to investigate the sintering characteristics of BCSAF cement clinkers. Four BCSAF clinkers with different compositions were examined. High-temperature microscopy, quantitative x-ray powder diffraction analysis and scanning electron microscopy were used to analyse sintering features and phase composition. The results show that the use of wastes from the production of manganese and magnesium metals, which were added to the raw materials to make clinker pellets, can significantly reduce the firing temperature of BCSAF clinker. The firing temperatures of clinkers with added wastes were below 1300°C, much lower than the temperature used for convention...

The Orvieto-Bagnoregio Ignimbrite: pyroxene crystal-chemistry and bulk phase composition of pyroclastic deposits, a tool to identify syn- and post-depositional processes

This study aims to characterize the crystallization conditions of the ignimbritic flux, the spatial and temporal evolution as well as the post-depositional processes of the Orvieto-Bagnoregio pyroclastic deposits from Bolsena Complex (Roman Magmatic Province, Italy) from a mineralogical and a geochemical point of view. Single-crystal X-ray diffraction together with electron-microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data were used to determine the crystal-chemistry of ten clinopyroxene samples from three outcrops of the Bolsena Complex: Orvieto, Bagnoregio and Porano. In addition, quantitative X-ray powder diffraction analyses of amorphous and crystalline phases by the Rietveld method were performed both on the bulk rock and on the juvenile products (mainly pumices and scoriae). The chemical composition and lattice parameters of the Orvieto and Bagnoregio clinopyroxenes indicate diopsides with a common mineralogical and petrogenetic affinity, but slightly different crystallization conditions from the samples of the Porano deposit. Cell volume and M1 polyhedral volume indicate a very low pressure of crystallization in comparison to those calculated for other eruptive centres of the Roman Magmatic Province (Sabatini, Vico and Alban Hills). Notwithstanding a common very high REE content in clinopyroxenes, the decrease of the REE content from the bottom to the top of the stratigraphic sequence of Orvieto is interpreted as an indication of the chemical zoning of the magmatic chamber. The bulk mineralogical composition is characterized by the presence of clinopyroxene, biotite, anorthite, leucite, analcime and zeolite, in particular phillipsite and chabazite. The Orvieto sequence is affected by strong differences in the amorphous content ranging from 1.3 to 82.0 wt%, as well as in the sanidine/zeolite ratio: sanidine content changes from 15.5 to 55.9 wt% and chabazite from 3.4 to 68.4 wt%. The large amount of zeolites along the pyroclastic sequence testifies that the Orvieto-Bagnoregio Ignimbrite was emplaced by hydromagmatic eruption at quite high temperatures with diffuse zeolitization that indicates strong variations in the chemical-physical composition of the pyroclastic flows which in turn have influenced the post-depositional processes and the cohesion of the rock.

Structural characteristics of cordierite/steatite ceramics sintered from mixtures containing pore-forming organovermiculite

The preceramic mixtures appropriate to the composition of cordierite are composed of talc, kaolinite and vermiculite (Ver), and/or organovermiculite (Ver-org) as a pore-forming agent. The preceramic mixtures for sintering at 1300°C were prepared in two different ways, loosely in crucibles and compressed into pellets. Structural characterization of cordierite/steatite ceramic was performed using X-ray powder diffraction (XRD), FTIR spectroscopy, scanning electron microscopy analysis and porosity measurement. The ceramic samples showed (1) bimodal meso-macropore size distribution and unimodal macropore size distribution, when the preceramic mixtures included Ver and Ver-org, respectively, and (2) higher porosity when sintering mixtures occurred in crucibles in comparison with pellets. The XRD patterns and quantitative XRD phase analysis revealed cordierite/steatite ceramics in the composition of indialite (IND) and two orthorhombic forms of enstatite: protoenstatite (PEN) and orthoenstatite (OREN). All cordierite/steatite samples contained a greater amount of PEN than OREN and a slightly higher quantity of IND when sintered in crucibles compare to pellets. The ceramic samples prepared from the preceramic mixtures with twice the amount of Ver-org contained a high quantity of IND (91vol%), PEN (about 9vol%) and no OREN. The unit cell parameter c in comparison with the pure IND was about 0.001–0.003nm shorter at all INDs. The pore-forming Ver-org supports structural substitution of cations during crystallization of IND with the substitution Ca0.50Mg1.50–Ca0.25Mg1.75. The IR spectra in the 400–1600cm−1 region confirmed the presence of cordierite and steatite.

Quantitative X-Ray Powder Diffraction Analysis of Portland Cements: Proficiency Testing for Laboratory Assessment

Abstract Quantitative X-ray powder diffraction analysis (QXRD) is being used within the cement industry for phase characterization of hydraulic cement. The current ASTM standard test method for powder diffraction analysis of cements provides guidance, but not an explicit method, for quantifying phase concentrations. The standard utilizes qualification criteria, where an analysis of a set of certified reference materials must fall within stated precision and bias limits. Validation of X-ray powder diffraction analyses by the Rietveld method is particularly important because the normalization inherent in the mass fraction calculations can obscure accuracy problems. Currently, the only certified reference materials for phase abundance are a set of NIST SRM clinkers, which lack the calcium sulfate and carbonate phases found in portland cements. A set of portland cements was distributed to 29 laboratories for analysis according to each lab’s individual protocols. The objective was to provide each lab with quantitative feedback on its precision and accuracy performance. The results from all the labs are presented graphically with Youden plots that incorporate ranking to illustrate relative lab precision and accuracy based upon a consensus mean for each phase and ASTM C1365 performance qualification criteria. Labs that fall outside of the compliance limits are provided with information via the Youden plots to assess their systematic and random error. Proficiency testing of this sort provides participating laboratories with a quantitative assessment of their performance relative to peers using a wider range of materials encompassing the broad spectrum of modern hydraulic cement production. These newer materials may include, for example, the calcium sulfate phases and the limestone additions that have become commonplace in today’s cements. Such a quantitative assessment could be used to qualify laboratories and may be stipulated in a specification.

Thermoelectric performance of multiphase XNiSn (X = Ti, Zr, Hf) half-Heusler alloys

Quantitative X-ray powder diffraction analysis demonstrates that mixing Ti, Zr and Hf on the ionic site in the half-Heusler structure, which is a common strategy to lower the lattice thermal conductivity in this important class of thermoelectric materials, leads to multiphase behaviour. For example, nominal Ti0.5Zr0.5NiSn has a distribution of Ti1−xZrxNiSn compositions between 0.24 ≤ x ≤ 0.70. Similar variations are observed for Zr0.50Hf0.5NiSn and Ti0.5Hf0.5NiSn. Electron microscopy and elemental mapping demonstrate that the main compositional variations occur over micrometre length scales. The thermoelectric power factors of the mixed phase samples are improved compared to the single phase end-members (e.g. S2/ρ = 1.8 mW m−1 K−2 for Ti0.5Zr0.5NiSn, compared to S2/ρ = 1.5 mW m−1 K−2 for TiNiSn), demonstrating that the multiphase behaviour is not detrimental to electronic transport. Thermal conductivity measurements for Ti0.5Zr0.5NiSn0.95 suggest that the dominant reduction comes from Ti/Zr mass and size difference phonon scattering with the multiphase behaviour a secondary effect.

Application of High Temperature Quantitative X-Ray Powder Diffraction on Determination of Ternary System

This paper has put forward a high-temperature quantitative X-ray powder diffraction analysis method for the determination of an isothermal section of a ternary system in comparison with a conventional method. In a three-phase region of the isothermal section at 1150 °C of Cu2O(CuO)-Al2O3-SiO2 pseudo-ternary system, the compositions of the solid phase points of three system points are determined according to the quantitative analysis of the crystalline phases in the samples carried out by Rietveld method. Then the liquid phase point of the three-phase region is determined according to the crosspoints of the tie lines of every pair of system point and solid phase point. The precisions of the analytical results have reached to be 0.1 ~ 5.0 %. By comparison, a good result is obtained for the determination of the liquid phase point of the three-phase region in the isothermal section at 1150 °C when the analytical results of high-temperature RQA analysis are used in determination of the isothermal section of the pseudo-ternary system.

X-ray powder diffraction study of polytetrafluoroethylene

Samples of polytetrafluoroethylene were studied by X-ray diffraction. A quantitative X-ray powder diffraction analysis of three components of the polymer was performed for the first time. All samples of polytetrafluoroethylene were found to be three-phase and consist of one crystalline and two amorphous phases. One of the amorphous phases is composed of low-molecular-weight products. The structure of the latter phase was established for the first time by X-ray diffraction methods and computer simulation.

Leaching Mechanisms of Cr(VI) from Chromite Ore Processing Residue

Batch leaching tests, qualitative and quantitative x-ray powder diffraction (XRPD) analyses, and geochemical modeling were used to investigate the leaching mechanisms of Cr(VI) from chromite ore processing residue (COPR) samples obtained from an urban area in Hudson County, New Jersey. The pH of the leaching solutions was adjusted to cover a wide range between 1 and 12.5. The concentration levels for total chromium (Cr) and Cr(VI) in the leaching solutions were virtually identical for pH values >5. For pH values <5, the concentration of total Cr exceeded that of Cr(VI) with the difference between the two attributed to Cr(III). Geochemical modeling results indicated that the solubility of Cr(VI) is controlled by Cr(VI)-hydrocalumite and Cr(VI)-ettringite at pH >10.5 and by adsorption at pH <8. However, experimental results suggested that Cr(VI) solubility is controlled partially by Cr(VI)-hydrocalumite at pH >10.5 and by hydrotalcites at pH >8 in addition to adsorption of anionic chromate species onto inherently present metal oxides and hydroxides at pH <8. As pH decreased to <10, most of the Cr(VI) bearing minerals become unstable and their dissolution contributes to the increase in Cr(VI) concentration in the leachate solution. At low pH ( <1.5), Cr(III) solid phases and the oxides responsible for Cr(VI) adsorption dissolve and release Cr(III) and Cr(VI) into solution.

X-ray powder diffraction quantitative analysis of an amorphous SiO2–poly(methyl methacrylate) nanocomposite

Quantification of individual phases within a multiphase amorphous material has been achieved using a newly developed technique based on X-ray powder diffraction. The quantification method was developed during a study of an amorphous silica–poly(methyl methacrylate) (SiO2–PMMA) hybrid nanocomposite. The efficiency of the method as a quantifying tool for individual phases was demonstrated for samples of SiO2–PMMA prepared either by polymerization of methyl methacrylate in the presence of amorphous SiO2or by mechanically mixing known quantities of the individual and pre-prepared SiO2and PMMA materials. The weight percentages of amorphous SiO2in the nanocomposites as determined by application of the new technique were analogously found to be 29%, a result that was supported by thermogravimetric analysis and helium picnometry measurements.

Resonance character of polymorphic transformations for the phase transition α′ L → β-Ca2SiO4

Experimental results are presented showing that rapid cooling of dicalcium silicate is accompanied by delay of structural processes, which leads to a decreasing in temperature of the phase transition α′L → β-Ca2SiO4. As starting materials, nepheline ore and limestone were used. In preparing the charge, the dosage of starting components was calculated for obtaining a molar ratio of CaO/SiO2 = 2.0. From the charge, the series of samples was prepared. Each of the samples was sintered to t = 1250°C with subsequent keeping of the material at this temperature for 30 min. Then the samples were subjected to rapid cooling in air to t = 750, 650, 550, 450, 350, 250, 150, and 25°C. By means of quantitative X-ray powder diffraction analysis using a DRON-3 setup, the content of α′L and β-Ca2SiO4 was determined in the samples. The data allow us to suppose the occurring polymorphic transformations in dicalcium silicate have a resonance character.

Primary study of the isothermal phase diagram of the Cu 2O-Al 2O 3-SiO 2 ternary system at 1150°C in air

The isothermal phase diagram of the Cu 2O-Al 2O 3-SiO 2 ternary system at 1150°C was reported for the samples which were prepared from sol-gel method and quenched by water after being heated at 1150°C for 12 h. Based on the conventional X-ray powder diffraction (XRD) and in situ high-temperature XRD quantitative analysis, in addition to scanning electron microscopy measurement, the phase identification was achieved. Combining the deduction from the component phase diagrams of the binary systems using the phase equilibrium theorem, the primary isothermal phase diagram was plotted over the composition area Cu 2O-mullite-SiO 2. In this area, the approximate composition areas of two two-phase regions and one three-phase region, (L 2 + Cr), (L 2 + M), and (L 1 + L 2 + Tr), were determined. Moreover, the precise composition areas of both of the three-phase regions (L 2 + Cr + M) and (L 2 + M + A) were determined according to the results of conventional and in situ high-temperature XRD quantitative analysis by Rietveld method.

The application of effective-medium theory for the nondestructive characterization of ceramic composites

In this paper is presented the application of effective-medium theory (EMT) on ferrite ceramic composites with various volume fractions of spinel phase in an M-hexaferrite matrix in order to determine the phase composition. The permeabilities, which were calculated with effective-medium theory from measured permeabilities of single-phase samples, were matched with measured effective permeability of composite samples. From analysis of composites sintered at two different temperatures it is also shown that by presented method one can detect the formation of new phases. In this way obtained volume fractions of spinel phase were compared with values from the X-ray powder diffraction (XRD) analysis and the nominal composition mass. It is shown that EMT quantitative phase determination of magnetic composites is comparable to XRD quantitative phase analysis and represents a simple and fast complementary alternative.

Formation of a specific layer on the surface of a metallic target interacting with a shaped-charge jet of boron-containing liners

Coatings on titanium targets are obtained under conditions of a shaped-charge explosion; the maximum microhardness of the coatings at certain segments of the target can reach 4000 kg/mm2. A conical liner with a cone angle of 20° prepared from a mixture of fine powders of amorphous boron and ammonium nitrate is used in the experiments. A comparative quantitative X-ray powder diffraction analysis of various segments of the coating is performed. The values of the unit cell parameters indicate the formation of complex phases. The dynamics of the results of the X-ray study with the cone angle of the liner decreasing from 45 to 20° is demonstrated.