Quantitative X-ray Diffraction Phase Analysis Research Articles

From geopolymers to zeolites: Synthesis and characterization of foamed FAU-X monoliths

A FAU-X-rich porous monolith has been obtained by means of an unconventional two-stage method consisting of the production of a foamed geopolymeric precursor and its subsequent conversion by means of a hydrothermal method. The influence of the conversion process parameters, such as NaOH concentration (0.1–2 M), treatment temperature (40–80 °C) and time (24–72 h) on the FAU-X crystallization was studied. Collected data revealed that the highest yield in terms of zeolite content and FAU-X/LTA ratio was obtained performing the hydrothermal treatment with a 0.5 M NaOH solution at 60 °C. The crystallization kinetics of FAU-X inside the geopolymer precursor was investigated by means of Synchrotron Radiation X-Ray Diffraction Quantitative Phase Analysis (SR-XRD-QPA). Results showed that the crystallization starts after an induction time of about 3 days, and the weight percentage of the zeolite in the sample raises up to about 78% after 20 days of treatment. The highest yield in terms of zeolite content, about 80% of FAU-X and 6% of LTA, was reached at 20 days. Finally, Scanning Electron Microscopy (SEM) analysis showed the presence of well-defined octahedral crystals either on the pore surface or in the bulk of the sample starting from 3 days of hydrothermal treatment.

Evolution of Microstructure and Elements Distribution of Powder Metallurgy Borated Stainless Steel during Hot Isostatic Pressing

Prepared by powder metallurgy process incorporating atomization and hot isostatic pressing (HIP) sintering at six different temperatures from 600 to 1160 °C, borated stainless steel (BSS) containing boron content of 1.86 wt% was studied. The phase of BSS, relative density of different temperature, microstructure, elemental distribution, and mechanical properties were tested and analyzed. The phases of the alloy were calculated by the Thermo-Calc (2021a, Thermo-Calc Software, Solna, Sweden) and studied by quantitative X-ray diffraction phase analysis. The distributions of boron, chromium, and iron in grains of the alloy were analyzed by scanning electron microscopy and transmission electron microscope. The grain size distributions and average grain sizes were calculated for the boron-containing phases at 900, 1000, 1100, and 1160 °C, as well as the average grain size of the austenite phase at 700 and 1160 °C. After undergoing HIP sintering at 900, 1000, 1100, and 1160 °C, respectively, the tensile strength and ductility of the alloy were tested, and the fracture surfaces were analyzed. It was found that the alloy consisted of two phases (austenite and boron-containing phase) when HIP sintering temperature was higher than 900 °C, and the relative density of the prepared alloys was higher than 99% when HIP temperature was higher than 1000 °C. According to the boron-containing phase grain size distribution and microstructure analysis, the boron-containing phase precipitated both inside the austenite matrix and at the grain boundaries and its growth mechanism was divided into four steps. The tensile strength and elongation of alloy were up to 776 MPa and 19% respectively when the HIP sintering was at 1000 °C.

Effect of Heat Treatment Temperature on Microstructure and Properties of PM Borated Stainless Steel Prepared by Hot Isostatic Pressing.

Borated stainless steel (BSS) with a boron content of 1.86% was prepared by a powder metallurgy process incorporating atomization and hot isostatic pressing. After solution quenching at 900–1200 °C, the phase composition of the alloy was studied by quantitative X-ray diffraction phase analysis. The microstructure, fracture morphology, and distributions of boron, chromium, and iron in grains of the alloy were analyzed by field-emission scanning electron microscopy with secondary electron and energy-dispersive spectroscopy. After the coupons were heat treated at different temperatures ranging from 900 to 1200 °C, the strength and plasticity were tested, and the fracture surfaces were analyzed. Undergoing heat treatment at different temperatures, the phases of the alloy were austenite and Fe1.1Cr0.9B0.9 phase. Since the diffusion coefficients of Cr, Fe, and B varied at different temperatures, the distribution of elements in the alloy was not uniform. The alloy with good strength and plasticity can be obtained when the heat treatment temperature of alloy ranged from 1000 to 1150 °C while the tensile strength was about 800 MPa, with the elongation standing about 20%.

Quantitative Phase Analysis by X-ray Diffraction—Doping Methods and Applications

X-ray powder diffraction is an ideal technique for the quantitative analysis of a multiphase sample. The intensities of diffraction lines of a phase in a multiphase sample are proportional to the phase fraction and the quantitative analysis can be obtained if the correction for the absorption of X-rays in the sample is performed. Simple procedures of quantitative X-ray diffraction phase analysis of a multiphase sample are presented. The matrix-flushing method, with the application of reference intensities, yields the relationship between the intensity and phase fraction free from the absorption effect, thus, shunting calibration curves or internal standard procedures. Special attention is paid to the doping methods: (i) simultaneous determination of the fractions of several phases using a single doping and (ii) determination of the fraction of the dominant phase. The conditions to minimize systematic errors are discussed. The problem of overlapping of diffraction lines can be overcome by combining the doping method (i) and the individual profile fitting method, thus performing the quantitative phase analysis without the reference to structural models of particular phases. Recent suggestions in quantitative phase analysis are quoted, e.g., in study of the decomposition of supersaturated solid solutions—intermetallic alloys. Round Robin on Quantitative Phase Analysis, organized by the IUCr Commission on Powder Diffraction, is discussed shortly. The doping methods have been applied in various studies, e.g., phase transitions in titanium dioxide, biomineralization processes, and phases in intermetallic oxide systems and intermetallic alloys.

Microstructural stability of heat-resistant high-pressure die-cast Mg-4Al-4Ce alloy

AbstractThe thermal stability of Al-RE (rare earth) intermetallic phases with individual RE for heat-resistant high-pressure die-casting Mg–Al–RE alloys is investigated. The results of this study show that the main strengthening phase of Mg-4Al-4Ce alloy is Al11Ce3, whose content is about 5 wt.% according to quantitative X-ray diffraction phase analysis. The Al11Ce3 phase appears to have high thermal stability at 200 °C and 300 °C, while phase morphology change with no phase structure transition could occur for Al11Ce3 when the temperature reaches 400 °C. Furthermore, besides the kinds of rare earths and temperature, stress is also an influencing factor in the microstructural stability of Mg-4Al-4Ce alloy.

Al-Nd intermetallic phase stability and its effects on mechanical properties and corrosion resistance of HPDC Mg-4Al-4Nd-0.2Mn alloy

Microstructural stability is a crucial but controversial issue for Mg-Al-RE alloys. It is important to study the thermal stability of Al-RE intermetallic phase with individual RE element. In this work, Mg-4Al-4Nd-0.2Mn (AlNd44, wt%) alloy with individual RE element Nd was prepared by high-pressure die-casting (HPDC). The microstructure, microstructural stability and its effects on tensile properties and corrosion behavior were investigated. The results show that the HPDC AlNd44 alloy has two intermetallic phases, i.e., acicular Al11Nd3 and particulate Al2Nd, which are distributed at grain/dendritic boundary regions and form reticular structure. According to the quantitative X-ray diffraction phase analysis, the content of Al11Nd3 and Al2Nd phases is 2.5 wt% and 1.8 wt%, respectively. Both the two phases appear to be thermally stable at 473 K. While the acicular Al11Nd3 phase has a tendency to decompose at temperature up to 573 K, and would decompose to particulate Al2Nd phase thoroughly at 673 K. Moreover, Al2Nd phase would also partly decompose at temperature above 573 K. The alloy in as-cast state, with an intermetallic skeleton at grain/dendritic boundary regions, exhibits relatively high tensile properties and corrosion resistance. In contrast, the alloy after annealing at 673 K has the worst tensile properties and corrosion resistance due to the obvious phase transition and microstructure change.

Microstructures and mechanical properties of Gd2Zr2O7/ZrO2(3Y) ceramics

Gd2Zr2O7/ZrO2(3Y) composite ceramics were prepared by vacuum sintering using Gd2Zr2O7 and ZrO2(3Y) nanoparticles. The ceramics were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), the three-point-bending technique and single-edge-notched-beam tests. The effect of various proportions of ZrO2(3Y) on the phase composition, microstructure, bending strength and fracture toughness of the final Gd2Zr2O7/ZrO2(3Y) composite ceramics was also analyzed. The change from m-ZrO2 to t-ZrO2 phase contents, before and after fracture, was measured using XRD quantitative phase analysis. The results confirm that, with the increasing content of ZrO2(3Y), a phase transition from solid solution to saturated precipitation occurs and the bending strength and fracture toughness of the samples increase gradually. When the content of ZrO2(3Y) reached 95vol.%, the Gd2Zr2O7/ZrO2(3Y) composite ceramics had a bending strength of 547MPa and a fracture toughness of 5.5MPam1/2, indicating that stress-induced phase transformation toughening was an efficient way to increase the mechanical properties of the Gd2Zr2O7 ceramics.

Phase composition and surface properties of nylon-6 nanofibers prepared by nanospider technology at various electrode distances

Phase composition, morphology and surface properties of nylon-6 nanofibers prepared by Nanospider technology have been studied for dependence on spinning distance using a combination of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrokinetic analysis, and scanning electron and transmission electron microscopy (SEM, TEM). The effect of the electric field strength on the nanofiber phase composition was investigated via the variable distance of the electrodes. Quantitative XRD phase analysis revealed the dependence of the phase composition on the electrode distance, which in the case of roller electrospinning, differs from that by melt spinning. A combination of XRD, XPS, and TEM suggested a core-shell structure model of the nanofibers. The XPS and electrokinetic analysis revealed the difference in surface chemistry and zeta potential at the face and reverse side of the nanofiber textile adjacent to a polypropylene (PP) antistatic spunbond, which may be important in subsequent chemical modification of nanofiber textiles and in its use for tissue engineering.

Quantitative phase analysis by X-ray diffraction – Simple routes

<p> The elemental composition of a multiphase material can be obtained by means of chemical and spectroscopic techniques. However, these techniques face a great difficulty in distinguishing the chemical identity of the phases present in the material and in derivation of the fractions of particular phases. X-ray powder diffraction seems to be an ideal technique for the analysis of a multiphase material. Each crystalline phase of the material gives its characteristic diffraction pattern independently of the other phases; this fact makes it possible to identify the phase of interest and to determine its fraction. The intensities of diffraction lines of a given phase are proportional to its fraction and an appropriate quantitative analysis can be performed after the application of the correction for the absorption of X-rays in the material.</p><p class="IUCrfigurecaption"> The principles of quantitative X-ray diffraction phase analysis of a multiphase material are presented, with a special attention paid to the doping methods. The following methods are described: (<em>i</em>) determination of the fraction of a phase using repeated dopings, (<em>ii</em>) determination of the fraction of a phase using a single doping, (<em>iii</em>) simultaneous determination of the fractions of several phases using a single doping; (<em>iv</em>) determination of the fraction of the dominant phase. The applicability of the doping methods is stated and the optimum conditions to minimize systematic errors are discussed. Recent approaches in quantitative X-ray diffraction phase analysis are also mentioned in short.</p>

Structural-Phase State Analysis of Calcium Mono-Aluminate

The paper presents results of the Rietveld refinement method in X-ray diffraction quantitative phase analysis of calcium mono-aluminate, the mineral. It has been stated that the theoretical calcium mono-aluminate CaO⋅Al2O3. is a high-stable phase, mixing energy of which is equal to 16214,10 eV. Ab-initio calculations and Rietveld refinement method were used to identify die structural state of CaO⋅Al2O3.

The importance of factor analysis in quantitative and qualitative X-ray diffraction phase analysis

Abstract In the statistical treatment of measured data, factor analysis is often necessary. The methods involved can be used individually to emphasize the basic common factors in the group of variables; the factors produced can be then utilized as input data for other data analysis methods. The number of variables required to describe the system may be lowered, because the original variables may be correlated and, possibly, there is a smaller set of linearly independent variables. Thus, factor analysis is among the possible methods for the data analysis, when dealing with quantitative analytical measurements. Factor analysis of the measured data was used to lower the amount of variables in the analysis of steel; it was found that 94.5 % of the overall variance in the data can be attributed to three factors. Three original variables were assigned to these factors, lowering the number of required variables.

Effects of Mn-doping on the structure and biological properties of β-tricalcium phosphate

Doping calcium phosphates with trace elements that exist in bone tissues is beneficial in terms of cell–material interactions and in vivo performance of the bone grafts made thereof. Manganese (Mn) is an essential element for normal growth and metabolism of bone tissues, but studies reporting the effects of Mn-doping calcium phosphates are scarce. The present study investigated the influence of Mn-doping on the structure, morphology and biological properties of β-tricalcium phosphate [β-Ca3(PO4)2] (β-TCP). Mn-doped (MnTCP) powders, with Mn contents varying from 0 to 10mol%, were obtained through an aqueous precipitation method followed by heat treatment at 800°C. The successful incorporation of Mn into β-TCP structure was proved through quantitative X-ray diffraction (XRD) phase analysis coupled with structural Rietveld refinement. Increasing Mn concentrations led to decreasing trends of a- and c-axis lattice parameters, and Mn-doping also significantly affected the morphology of β-TCP powders. In vitro proliferation and differentiation assays of MC3T3-E1 osteoblastic-like cells, grown in the presence of the powders, revealed that the biological benefits of Mn-doped β-TCP are limited to lower Mn incorporation levels and potentially related to their surface microstructure. The Mn1-βTCP composition revealed the best set of bioactivity properties, potentially a good candidate for future applications of β-TCP materials in osteoregeneration.

Stoichiometry effect on Cu2ZnSnS4 thin films morphological and optical properties

Thin films of Cu2ZnSnS4 (CZTS) were prepared by sulfurization of multilayered precursors of ZnS, Cu, and Sn, changing the relative amounts to obtain CZTS layers with different compositions. X-Ray Diffraction (XRD), Energy Dispersive X-Ray spectroscopy, and SEM were used for structural, compositional, and morphological analyses, respectively. XRD quantitative phase analysis provides the amount of spurious phases and information on Sn-site occupancy. The optical properties were investigated by spectrophotometric measurements and Photothermal Deflection Spectroscopy. These films show a clear dependence of the optical and microstructural properties on the tin content. As the tin content increases we found: (i) an increase in both crystalline domain and grain size, (ii) an abrupt increase of the energy gap of about 150 meV, from 1.48 to 1.63 eV, and (iii) a decrease of sub-gap absorption up to two orders of magnitude. The results are interpreted assuming the formation of additional defects as the tin content is reduced.

CZTS stoichiometry effects on the band gap energy

Abstract The considerable spread of Cu2ZnSnS4 (CZTS) optical properties reported in the literature is discussed in terms of material stoichiometry. To this purpose, kesterite thin films were prepared by sulfurization of multilayered precursors of ZnS, Cu and Sn, changing the relative amounts to obtain CZTS layers with different compositions. X-Ray Diffraction (XRD), Energy Dispersive X-Ray (EDX) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy were used for structural and compositional analysis. XRD quantitative phase analysis provides the amount of spurious phases and information on Sn-site occupancy. The optical properties were investigated by spectrophotometric and Photothermal Deflection Spectroscopy (PDS) measurements to assess the absorption coefficient of samples with different compositions. The PDS data show an increase of the sub-band absorption as the Sn content decreases. The results are interpreted assuming the formation of additional defects as the tin content is reduced. Those defects can also be responsible for the decrease of the band gap energy value as the Sn/Cu ratio is decreased.

Selected applications of Rietveld-XRD analysis for raw materials of the aluminum industry

In the last few decades, X-ray diffraction (XRD) systems have been paramount and irreplaceable in controlling bauxite exploration, as well as Bayer and reduction processes. XRD quantitative phase analysis in the aluminum industry witnessed a steady deployment of the Rietveld method, which at present progressively replaces existing methodologies in research and plant laboratories. Rietveld analysis not only helped to surpass traditional XRD calibration methods, it also opened the door for new applications previously not possible. The use of the Rietveld method to characterize selected materials unique to the aluminum industry, such as bauxite, red mud, and alumina is demonstrated and discussed. This paper also presents how synchrotron-based diffractograms obtained for bauxite and red mud samples allowed a much better understanding of mineralogical representation, and made it possible to leverage their Rietveld quantification. Despite clear advantages, the Rietveld method also has limitations that are revealed. For alumina phase quantification, a dedicated Rietveld analytical program was built with structure data for eight alumina mineralogical phases: alpha, beta (β-Al2O3 = Na2O•11Al2O3), delta, gamma (2), kappa, sigma, and theta. The paper gives unique examples of phase quantification in aluminas of various origins and phase composition.

Dispersion states and acid properties of SiO2-supported Nb2O5

Nb{sub 2}O{sub 5}/SiO{sub 2} samples were prepared by the incipient-wetness impregnation method using niobium oxalate aqueous solution. The microstructure and dispersion process of the niobia species supported on SiO{sub 2} were characterized by means of power X-ray diffraction (XRD), laser Raman spectroscopy (LRS), and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The acid properties were investigated by the method of Hammett indicator and Pyridine adsorption infrared (Py-IR) spectroscopy. The results showed that the dispersion process of Nb{sub 2}O{sub 5} was performed by consuming surface hydroxyl groups of the amorphous SiO{sub 2} support. The aggregation of niobia species led to the formation of microcrystalline particles, so that there was no a clear monolayer dispersion capacity for Nb{sub 2}O{sub 5} supported on amorphous SiO{sub 2}. Furthermore, the catalytic activities of the as-prepared samples were evaluated by the condensation reaction of iso-butene (IB) and iso-butyraldehyde (IBA) to form 2,5-dimethyl-2,4-hexadiene (DMHD). The catalytic activities of the as-prepared samples for the condensation and their acid properties were strongly affected by the dispersion states. - Graphical abstract: The acid amount and strength of Nb{sub 2}O{sub 5}/SiO{sub 2} samples varied with the increase of Nb{sub 2}O{sub 5} loading. The catalytic activities of the as-prepared samples for the condensationmore » and their acid properties were strongly affected by the dispersion states. - Highlights: • The dispersed process of Nb{sub 2}O{sub 5} was completed by consuming surface hydroxyl groups of SiO{sub 2}. • XRD quantitative phase analysis is not applicable for oxides dispersing on amorphous support. • The catalytic activity of Nb{sub 2}O{sub 5}/SiO{sub 2} is closely related to the dispersion state of SiO{sub 2}.« less

Comparison of the hot corrosion of nanostructured and microstructured thermal barrier coatings

Thermal barrier coatings of nanostructured and microstructured yttria stabilized zirconia (YSZ) were deposited on GH4049 substrate by air plasma spray, respectively. Hot corrosion behaviors of both coatings were evaluated in comparative aspects. Results revealed that the nanostructured YSZ displayed higher resistance to the hot corrosion attack by Na2SO4 and V2O5. It was also shown, through X-ray diffraction quantitative phase analysis, that the nanostructured YSZ had good resistance to the tetragonal-monoclinic phase transformation during the hot corrosion process.

Crystallite Size—Is It a New Predictor for Renal Stone Burden?

To evaluate the importance of stone composition and crystallite size in the formation of ultimate stone burden. Crystallite is the smallest building block, which is unique in size and architecture for each type of stone component. Currently, the knowledge about the clinical importance of crystallite size is very limited. The results of quantitative X-ray diffraction phase analysis performed on 286 kidney stones extracted during endourological surgery or expelled spontaneously were retrospectively analyzed. Stone composition and crystallite size were determined and were compared to the burden occupying the pelvicalyceal system. A total of 286 renal stones were analyzed. Stones were low burden and high burden in 242 and 44 of cases, respectively. We observed statistically significant association of phosphates and urates with high-burden stones in contrast to oxalates, which formed mainly low-burden stones. Crystallite sizes were available for 179 stones. Large-sized crystallites of calcium oxalate monohydrate and hydroxyl apatite formed low-burden stones, whereas small-sized crystallites formed staghorn stones. Struvite and urates had a uniform average size of crystallites. Oxalate stones have statistically significant association with smaller stones, whereas high-burden calculi are significantly associated with urates and phosphates, especially the struvite type. The smaller the crystallite size is to start with, the larger will be the ultimate stone burden. This rule is followed by calcium oxalate monohydrate and Apatite minerals.

Quantitative X-ray diffraction phase analysis of poorly ordered nontronite clay in nickel laterites

Studies of the extraction of nickel from low-grade laterite ores require a much better quantitative understanding of the poorly ordered mineral phases present, including turbostratically disordered nontronite. Whole pattern refinements with nontronite X-ray diffraction data from a Western Australian nickel deposit (Bulong) using a nontronite lattice model (Pawley phase) with two space groups (P3 andC2/m) and a peaks phase group model were performed to improve the accuracy of quantitative X-ray diffraction of nickel laterite ore samples. Modifications were applied when building the new models to accommodate asymmetric peak shape and anisotropic peak broadening due to the turbostratic disorder. Spherical harmonics were used as convolution factors to represent anisotropic crystal size and strain and asymmetric peak shape when using the lattice model. A peaks phase group model was also developed to fit the anisotropic peak broadening in the nontronite pattern. The quantitative results of the new Pawley phase and peaks phase group models were compared and verified with synthetic mixtures of nontronite, quartz and goethite simulating various West Australian laterite ore compositions. The models developed in this paper demonstrate adequate accuracy for quantification of nontronite in the synthesized reference materials and should be generally applicable to quantitative phase analysis of nontronite in nickel laterite ore samples.

X-ray diffraction and SEM study of kidney stones in Israel: quantitative analysis, crystallite size determination, and statistical characterization

Urinary calculi have been recognized as one of the most painful medical disorders. Tenable knowledge of the phase composition of the stones is very important to elucidate an underlying etiology of the stone disease. We report here the results of quantitative X-ray diffraction phase analysis performed on 278 kidney stones from the 275 patients treated at the Department of Urology of Hadassah Hebrew University Hospital (Jerusalem, Israel). Quantification of biominerals in multicomponent samples was performed using the normalized reference intensity ratio method. According to the observed phase compositions, all the tested stones were classified into five chemical groups: oxalates (43.2%), phosphates (7.7%), urates (10.3%), cystines (2.9%), and stones composed of a mixture of different minerals (35.9%). A detailed analysis of each allocated chemical group is presented along with the crystallite size calculations for all the observed crystalline phases. The obtained results have been compared with the published data originated from different geographical regions. Morphology and spatial distribution of the phases identified in the kidney stones were studied with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). This type of detailed study of phase composition and structural characteristics of the kidney stones was performed in Israel for the first time.