In many ways, studies of materials and minerals by powder-diffraction techniques are complementary, with techniques honed in one field equally applicable to the other. Many of the example techniques described within this paper were developed for analysis of functional materials and subsequently applied to minerals. However, in a couple of cases, the study of new minerals was the initiation into techniques later used in materials-based studies. Hopefully they will show that the study of new minerals structures can provide opportunities to add new methodologies and approaches to future problems. In keeping with the Australian X-ray Analytical Association many of the examples have an Australian connection, the materials ranging from organics to battery materials.

There is a growing need for environmental scientists, geoscientists, and analysts skilled in the use of X-ray fluorescence spectrometry and X-ray diffractometry. The challenge for educators is how to inspire, teach, and make the next generation of professional X-ray users and analysts ready for employment. In this paper, we present vignettes from teaching applications of X-ray analytical techniques at three scaffolded levels, from senior high school students, undergraduate science students, to postgraduate researchers. At each of these levels the pedagogical complexity increases, from simple data use at high school, to observing how data are generated and being able to constrain analytical uncertainty at the undergraduate level, to generating high-quality data at the postgraduate level. In all cases, transportable equipment is used in on-site analytical programs to inform the experimental design, level of sampling required, and research outcomes.

Compounds in the BaxSr3−xTiNb4O15 series with x = 0.0–3.0 were synthesised. Synchrotron X-ray diffraction data were collected for each member synthesised. Rietveld refinements were performed for all compositions. A composition-dependent phase transition between orthorhombic and tetragonal symmetries was found. Cation ordering was observed between barium and strontium atoms in the two distinct A site cavities

Since Boeke's finding of a reversible phase transition of calcite (calcium carbonate, CaCO3) at elevated temperatures [Boeke, H. E. (1912). Neues Jahrb. Mineral. 1, 91–121], and following W. L. Bragg's determination of the structure of the room-temperature Phase I [Bragg, W. L. (1914). Proc. R. Soc. Lond. A 89, 468–489.], the high-temperature Phase V of calcite has been an enduring mystery. Here, we summarize a paper on the structure of Phase V [Ishizawa, N., Setoguchi, H. and Yanagisawa, K. (2013). Sci. Rep. 3, 2832], as well as the intermediate Phase IV which exists between Phases I and V, and add new aspects. An in situ single-crystal X-ray diffraction study revealed that the I–IV and IV–V transitions occurred reversibly at approximately 985 and 1240 K, respectively, in a carbon dioxide atmosphere. Phase V was stable only over a narrow temperature range between 1240 and 1275 K. The crystal decomposed immediately at temperatures above 1275 K, leaving a nanoporous calcium oxide reaction product which retained the shape of the parent calcite crystal. The I–IV transition can be described as an orientational order/disorder transition of the carbonate group, occurring within the same space group $R\bar 3c$. In Phase V, the oxygen sublattice is melted. The joint-probability density function obtained from the anharmonic atomic displacement parameters of the oxygen atoms revealed that the oxygen triangles of the carbonate group in Phase V do not sit still at specified Wyckoff positions in the space group $R\bar 3m$, but are instead distributed with equal probability along the undulated circular orbital about the central carbon. The carbonate group in Phase V is no longer flat on the basal plane when the oxygen triangle comes to troughs or peaks in the undulated orbital, but is instead deformed like an umbrella. Assuming that the oxygen triangle migrates about carbon, the carbonate group should repeat the umbrella inversion in Phase V as a function of time. Finally, possible thermal decomposition mechanisms of calcite are briefly discussed.

Pulsed tandem gas metal arc welding (PT-GMAW) is being developed to increase productivity and minimise weld-induced distortion in ship-building. The PT-GMAW process was used in pulse–pulse mode to butt-weld two different strength and thickness steels; the residual stress and hardness profiles of the welds are reported and correlated.

Recent developments in instrumentation mean that chemical analysis of large drill cores taken for geological purposes can be performed rapidly at sub-millimetre scales using core scanners equipped with energy-dispersive X-ray fluorescence spectrometers. The present study describes the development of a calibration for the Itrax Core Scanner (Cox Analytical, Sweden), intended for whole cores of coal-seam sections, without the need for sample preparation. The calibration was developed for key major elements (Al, Si, P, S, K, Ca, Ti, and Fe) based on pressed pellets of reference coals, allowing semi-quantitative and, at times, quantitative analyses. The influence of core curvature and surface roughness compared with an ideal flat-surface was also examined using model samples, and their influence on the apparent sample composition evaluated.

The evolution of the 003 reflection of the layered Li(Ni,Co,Mn)O2 (CGR) and Li(Ni,Co,Al)O2 (NCR) cathodes in commercial 18650 lithium-ion batteries during charge/discharge were determined using in situ neutron powder diffraction. The 003 reflection is chosen as it is the stacking axis of the layered structure and shows the largest change during charge/discharge. The comparison between these two cathodes shows that the NCR cathode exhibits an unusual contraction near the charged state and during the potentiostatic step, where the potentiostatic step is recommended by the manufacturer. This feature is not shown to the same degree by the CGR cathode. The behavior is likely related to the compositions of these cathodes, the amount of Li/Ni site mixing and the presence of Al or Mn.

Sterilization of soils and sediments can release them from quarantine restrictions. Gamma irradiation is effective at sterilization but can damage materials and in so doing affect their suitability for environmental research. Duplicate samples of a wide range of mineral soils and sediments were subject to an acetic acid extraction before and after 50 kGy gamma irradiation. This amount of gamma irradiation did not affect the leachability of a range of analytes from the soils and sediments.

X-ray diffraction and scattering on a single multipurpose X-ray platform have been used to probe the structure, composition, and thermal behavior of TiO2 nanoparticles ranging in size from 1 to 10 nm. Ambient and non-ambient Bragg diffraction, small-angle X-ray scattering (SAXS), as well as total scattering and pair-distribution function (PDF) analysis are combined to obtain a comprehensive picture of the samples. At these ultrasmall particle-size dimensions, SAXS and PDF prove powerful in distinguishing the salient features of the materials, in particular the size distribution of the primary particles (SAXS) and the identification of the TiO2 polymorphs (PDF). Structural features determined by X-ray scattering techniques are corroborated by high-resolution transmission electron microscopy. The elemental make-up of the materials has been measured using X-ray fluorescence spectrometry and energy-dispersive X-ray analysis.

The formation and decomposition of silico-ferrite of calcium and aluminium (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using in situ synchrotron and laboratory X-ray diffraction (XRD) and neutron diffraction (ND). An external standard approach for determining absolute phase concentrations via Rietveld refinement-based quantitative phase analysis is discussed. The complementarity of in situ XRD and ND in characterising sinter phase formation and decomposition is also shown, with the volume diffraction afforded by the neutron technique reducing errors in the quantification of magnetite above ~1200 °C. Finally, by collecting 6 s laboratory XRD datasets and using a heating rate of 175 °C min−1, phase formation and decomposition have been monitored under heating rates more closely approximating those encountered in industrial iron ore sintering.

The structural evolution of the “zero-strain” Li4Ti5O12 anode within a functioning Li-ion battery during charge–discharge cycling was studied using in situ neutron powder-diffraction, allowing correlation of the anode structure to the measured charge–discharge profile. While the overall lattice response controls the “zero-strain” property, the oxygen atom is the only variable in the atomic structure and responds to the oxidation state of the titanium, resulting in distortion of the TiO6 octahedron and contributing to the anode's stability upon lithiation/delithiation. Interestingly, the trend of the octahedral distortion on charge–discharge does not reflect that of the lattice parameter, with the latter thought to be influenced by the interplay of lithium location and quantity. Here we report the details of the TiO6 octahedral distortion in terms of the O–Ti–O bond angle that ranges from 83.7(3)° to 85.4(5)°.

A number of synchrotron X-ray fluorescence microprobes (XFMs) around the world offer synchrotron X-ray microdiffraction (μXRD) to enhance mineral phase identification in geological and other environmental samples. Synchrotron μXRD can significantly enhance micro X-ray fluorescence and micro X-ray absorption fine structure measurements by providing direct structural information on the identity of minerals, their crystallinity, and potential impurities in crystal structures. The information is useful to understand the sequestration of metals in mineral deposits, mineral processing residues, soils, or sediments. Synchrotron μXRD was employed to characterize a surficial calcrete uranium (U) ore sample and to illustrate its usefulness in conjunction with U LIII μXANES analysis. μXRD and U LIII μXANES revealed that the mineral carnotite [K2(UO2)2(V2O8)·nH2O, n = 0, 1, 2, or 3] was not the sole U bearing mineral phase present and that surface complexes and or an amorphous precipitate were present as well. Unit-cell analysis from the μXRD patterns revealed that the interlayer spacing of carnotite was not uniform and that significant unit-cell volume expansions occurred likely because of variable cations (K+, Rb+, and Sr2+) and variably hydrated interlayer cations being present in the interlayer. Oriented specimen, single crystal effects, and the fixed orientation of the sample relative to the incident beam and the charge-coupled device camera limit the number of visible reflections and complicate mineral phase identification. With careful analysis of multiple structural analysis tools available at XFMs, however, a strong link between X-ray amorphous and X-ray crystalline materials in geologic and environmental samples can be established.

New quenched-in face-centred cubic fluorite-type materials were synthesised in the Bi2O3–Yb2O3–PbO system. After annealing in air at 500 °C for up to 200 h, each material underwent a conductivity-lowering structural transformation, thus making them unsuitable for use as solid electrolytes in solid-oxide fuel cells. For example, (BiO1.5)0.80(YbO1.5)0.17(PbO)0.03 underwent a fluorite- to Bi17Yb7O36-type orthorhombic transformation, indicative of long-range cation ordering, and (BiO1.5)0.80(YbO1.5)0.11(PbO)0.09 underwent a fluorite- to β-Bi2O3-type tetragonal transformation, indicative of long-range 〈001〉 oxide-ion vacancy ordering.

The use of high-speed detectors made X-ray diffraction (XRD) become an important tool for process control in mining and metal industries. Decreasing ore qualities and increasing prices for raw materials require a better control of processed ore and a more efficient use of energy. Traditionally quality control of iron ore sinter has relied on time-consuming wet chemistry. The mineralogical composition that defines the physical properties such as hardness or reducibility is not monitored. XRD analysis in combination with Rietveld quantification and statistical data evaluation using partial least-squares regression (PLSR) has been successfully established to determine the mineralogical composition and the Fe2+ content of iron ore sinter within an analysis time of less than 10 min per sample. A total of 35 iron ore sinter samples were measured and evaluated using PLSR and the Rietveld method. The results were compared with wet chemistry data. PLSR results show accuracy for the Fe2+ content of ±0.14%. No pure phases, crystal structures, or complex modeling of peak shapes are required. The Rietveld method was used to quantify the total phase composition of the samples. The Fe2+ content could be calculated from all phases present. Both methods take the full XRD pattern into account and can be simultaneously applied on the same measurement. PLSR was found to be the more robust method if only Fe2+ results are required. The Rietveld method helps predict other parameters such as the compressional strength of the sinter by monitoring all existing phases (e.g., larnite, C2S, or silico-ferrite of calcium and aluminum phases).

X-ray diffraction (XRD) was used to determine the temperature at which the transformation of Ce2O(CO3)2·H2O to ceria (CeO2) occurs under both a flow of nitrogen and air as a function of temperature. The Ce2O(CO3)2·H2O synthesised from Ce(NO3)3·6H2O and urea was further investigated using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results indicate that, under a flow of nitrogen, CeO2 is formed at temperatures greater than 500 °C and that this occurs via an as yet unidentified intermediate phase, which is present between 430 and 540 °C. Results obtained by the XRD correspond to those obtained using TGA, which show weight  losses commencing at 430 and at 465 °C. No further weight loss occurs above 540 °C, because of the formation of CeO2 as the stable product. The crystallite size was also determined and observed to increase with increasing temperature. Under a flow of air the transformation occurred at a lower temperature, as CeO2 was formed at 250 °C. SEM and TEM reveal the particles have a rod-shaped morphology which is retained after calcination. These results may be used to optimise synthesis methods to minimise crystallite size growth and reduce sintering that is undesirable in many applications, particularly catalysis.

Rietveld-based quantitative X-ray diffraction (QXRD) has been extensively used for mineralogical characterization in order to understand the reaction chemistry, and kinetics of minerals leaching and formation. This work presents examples where QXRD has been applied to understanding fundamental aspects of these two processes. Firstly, the co-processing of nickel laterites and sulphidic materials has the potential to offer several advantages that include the use of lower grade (including non-smeltable) concentrates, improvement in the rheological behaviour of the blends, and reduction in the use of sulphuric acid. The leaching kinetics and chemistry of mixed nickel laterite ore and sulphide concentrate were explored by the QXRD analysis of feed materials and, intermediates and final leach residues produced using controlled oxidation rates. Under high temperature (250 °C) and pressure oxidation (~40 to 45 atm.) conditions, sulphide minerals in the nickel concentrate underwent several oxidative hydrothermal transformations, and ferrous iron was oxidized and precipitated primarily as hematite. High recovery of nickel can be achieved with low acid consumption under these conditions. Secondly, iron precipitation/removal is an important down-stream process in hydrometallurgy. Moderate concentrations of ferrous iron can be oxidized using micro-organisms with oxidation rates several orders of magnitude faster compared with abiotic oxidation at ambient temperature and pressure. QXRD and chemical analysis have indicated that after oxidation, iron at pH ~2 mostly precipitates as jarosite with various amounts of K+, Na+, NH4+, and H3O+ incorporated into the structure. Bio-catalysed iron removal can be achieved with minimum copper and nickel losses at relatively low pH conditions.

The yttrium-based metal–organic framework, Y(btc) (btc = 1,3,5-benzenetricarboxylate), shows moderate uptake of methane (0.623 mmol g−1) and molecular oxygen (0.183 mmol g−1) at 1 bar and 308 K. Neutron powder-diffraction data for the guest-free, CD4-, and O2-loaded framework reveal multiple adsorption sites for each gas. Both molecular guests exhibit interactions with the host framework characterised by distances between the framework and guest atoms that range from 2.83 to 4.81 Å, with these distances identifying interaction most commonly between the guest molecule and the carboxylate functional groups of the benzenetricarboxylate bridging ligand of the host.

Rapid, on-line measurement of feedstock mineralogy is a highly attractive technology for the mineral processing industry. A Monte Carlo particle transport-based modelling technique has been developed to help design and predict the measurement performance of on-line energy-dispersive X-ray diffraction (EDXRD) analysers. The accuracy of the technique was evaluated by performing quantitative phase analysis on a suite of fifteen synthetic potash ore samples. The diffraction profile of each sample was measured with a laboratory EDXRD analyser and an equivalent profile was simulated in the Monte Carlo package. Linear regression analysis was used to determine the mineral abundances in each sample from both the measured and modelled profiles. Comparison of the results showed that the diffraction profiles and measurement accuracies obtained by simulation agree very well with the measured data.