Tag: Crystallinity

Pharmacetical applications of thermal analysis

Thermal analysis is widely used in the pharmaceutical industry to measure properties such as polymorphism, excipient compatibility, purity, melting points and humidity studies.

Texture Analysis of a Cu Wiring Film using the Orientation Distribution Function (ODF)

Since there is a strong relation between the material characteristics and the crystal orientation of metals and many other industrial materials, quantitative analyses of crystallites orientation and their distributions are of great importance. Pole figure measurements are a common method to quantitatively analyze orientation. In this Application Byte, we used the Orientation Distribution Function (ODF) to evaluate the crystallites orientation of a Cu wiring film from a pole figure measurement.

Quantitative analysis of a 3-component sample by DD (Direct Derivation) method

Quantitative analysis by powder X-ray diffraction has long been carried out using calibration curves, a
technique that requires preparing samples whose components are quantified, using pure or standard
substances to obtain calibration curves. In recent years, quantitative analysis without calibration curves has
become possible by calculating quantitative values from crystal structures. However, these methods require
the crystal structures of the materials, limiting the applicable substances. With the Direct Derivation method
introduced here, the quantitative weight fractions of individual crystalline phases can be derived from sets of
integrated intensities collected in a wide 2 range, together with chemical composition data.

Qualitative Analysis of an Ancient Glass Bead

The Oido tunnel tombs in Wakuyacho, Miyagi (Japan) are tumuli that have been constructed between the late 7th century and the early 8th century. During scientific investigations between 1962 and 1964, a glass bead with a spotted pattern (concentric circles) rare to Japan was excavated, which is believed to be originated in South Asia or Southeast Asia. By evaluating the colored portion of the glass bead using the SmartLab Automated Multipurpose X-ray Diffractometer, it was possible to determine its chemical composition and provide a scientific basis for assumptions on the fabrication technique and a reevaluation of its origin. The research was conducted by the Nara National Research Institute for Cultural Properties in 2013, and presented at the 31st Congress of the Japan Society for Scientific Studies on Cultural Properties in 2014.

Phase identification and orientation analysis for a thin film SOFC material using a 2D detector, Pole Figure, RSM

Thin films formed on substrates show various crystal phase and orientations depending on the materials and
manufacturing method. Therefore, phase identification is sometimes difficult by ordinary X-ray diffraction
(XRD) measurement. The diffraction image using a two-dimensional (2D) detector reveals the lattice constant
and the orientation for each crystal phase readily because the diffraction intensity distribution in the 2θ
direction and the distribution of the crystal orientation in the χ direction are observed simultaneously.

Quantitative analysis of polymorph impurities of tablets by transmission X-ray diffraction

In the tableting process for pharmaceuticals, it sometimes happens that the active pharmaceutical ingredient reacts with materials used as excipients, such as sugar or starch, and dehydration reactions, polymorph transitions and other processes may occur due to the pressure during tableting. In recent years, a need has arisen to check, in the shortest possible time, whether or not the active pharmaceutical ingredient maintains its original crystal system, and whether or not there are polymorph impurities. Furthermore, this must be done in the tableting process, while maintaining the tablet form. Therefore, we used a powder X-ray diffractometer to non-destructively measure the state of tablets in their original form, and evaluate the presence of the contained active pharmaceutical ingredient and polymorph impurities. By using a transmission-type parallel beam optical system, it is possible to obtain an accurate diffraction profile which does not depend on the sample form, and acquire information not only from the outside, but also from the inside of tablets. As a result of measurement, it was found that if polymorph impurities of the active pharmaceutical ingredient are about 1%, then their presence in the tablets could be confirmed in a measurement time of less than 10 minutes.

Measurement of microscopic regions using a high-speed 2-dimensional detector

Carbide tools used for cutting are provided with various types of coatings to improve durability. Previously, evaluation of the coating layer has been done using X-ray diffraction, but some users want to achieve rapid and simultaneous evaluation of factors such as site-dependent differences in composition, crystallinity and orientation. These evaluations can be easily done by employing the optical element and detector used in this report.

In-situ observation of structural changesaccompanying charging-discharging of cathode materials of lithium ion batteries

Controlling the state of the charge-discharge process is believed to be crucial for extending the life of lithium ion batteries. Therefore, it is not enough to simply observe the electrode structure in the 100% charged and discharged states, and there is a need to carry out in-situ observation of the relationship between depth of charge, depth of discharge and electrode structure. However, if materials are removed once from sealed batteries, the materials will react with the atmosphere, and the charge-discharge state will change due to peeling of electrodes. Thus there is a risk of the material changing into another structure, irrespective of the charge-discharge situation. As a result, with previous methods, it was difficult to observe changes in materials accompanying charging-discharging via an X-ray diffraction measurement. However, with batteries made using lithium ion battery cells for evaluation and testing, X-ray diffraction can be performed simultaneously with charge-discharge testing. Thus it is possible to carry out evaluation by directly relating changes in the state of samples to charge-discharge characteristics, without performing any additional work on the materials subjected to charge-discharge testing, such as opening seals or peeling electrodes.

High-speed in-situ measurement of melting process of metal using 2D detector

To capture the moment when materials change, such as during melting, solidification or crystal phase change,
by in-situ X-ray diffraction measurement, the acquisition time of the X-ray diffraction images at each
temperature needs to be as short as possible. 0D and 1D detectors take time to scan the detector and
prepare for operation. Conventional 2D detectors also have a problem in that the X-ray shutter needs to be
opened and closed between counting and reading the data. The HyPix-3000 hybrid pixel array
multi-dimensional detector in 2D mode can acquire X-ray diffraction images without scanning the detector.
The HyPix-3000 has two counters inside. Switching between them allows measurement without dead time.
These features enable shutterless measurement of 2D X-ray diffraction images, which makes it possible to
observe rapid changes in crystalline state.

High speed RSM of a III-nitride epitaxial film by 1D detection mode

Reciprocal space mapping (RSM) is an XRD technique used to evaluate lattice spacing and crystal orientation
distribution independently from each other, applied to the analysis of thin film samples such as epitaxial films.
Since a reciprocal space map requires multiple scans with various combinations of the scattering angle (2θ)
and the incident angle with respect to the sample (ω), it can take a relatively long time to collect the necessary
data in general. Combination of the 1D exposure mode of a 2D detector and high-speed scanning by the ω
axis enables data collection in a very short time, from several tens of seconds to several minutes,

Examination of the Growth Process of an Organic Thin Film by In-Plane XRD

The organic semiconductor pentacene has attracted a lot of attention for potential use in TFT (thin film
transistor) due to its high carrier mobility which approaches that of amorphous Si. However, controlling the
crystal phase and molecular orientation in the pentacene thin film is essential to obtain optimal characteristics.
In this example, we perform phase identification and evaluation of orientation of the pentacene molecules in
thin films different in thicknesses as well as crystallite size determination.

Elucidating the structure of mesoporous silica

X-ray diffraction measurements were carried out on two types of MCM-41. The d values in Fig. 1 do not arise from the atomic structure. They arise from the arrangement of the skeletal structure of the material, and therefore the values are large. As a result, the observed diffraction lines appear on the low angle side, as shown in Fig. 2. Transmission method measurement employing a small-angle optical system is also sometimes used with these samples, but measurement can also be done with a reflection method using a D/teX Ultra the high-speed 1D X-ray detector. As shown in Fig. 2, there is little statistical fluctuation, even with measurement time of 1 minute or less, and the minimum peak positions of d2 and d3 on the large-angle side can be clearly calculated. As shown in Table 1, the relative d values matched theoretical values for both Sample 1 and 2.

Difference between quantitative results using the WPPF method and the RIR method

In quantitative analysis using X-ray diffractometry, different quantification methods are used depending on factors such as the state of the sample and concentration of the measured components. The method using calibration curves is complicated by the need to procure standard samples, or prepare and measure samples, and thus, at present, there is a switch toward analysis using the WPPF (Whole Powder Pattern Fitting) method and the RIR (Reference Intensity Ratio) method. In the WPPF method, profile fitting is performed over a comparatively broad angular range, based on information about the crystal system and lattice constants. The RIR method uses RIR values listed in a database and integrated intensity of the maximum intensity curves. Both methods enable easy calculation of quantitative values by using dedicated analysis software.

Detection of minor peaks of iron-based samples using the D/teX Ultra high-speed 1D X-ray detector

If a high-speed 1-dimensional detector is used, and comparison is done under measurement conditions with the same resolution, it is possible to obtain an intensity approximately 100 times that of a scintillation counter (SC). However, if the sample contains elements with a high mass-absorption coefficient for the X-ray wavelength used, then there will be a major increase in the background due to fluorescent X-rays. The D/teX Ultra high-speed 1D X-ray detector has high energy resolution, and can greatly reduce the rise in background due to fluorescent X-rays from the sample by narrowing the detected energy range.

Crystal orientation measurements of samples containing coarse grains

Pole figure measurement is an important technique for determining the crystal orientation of a sample or calculating the volume fraction of the orientation. Especially for the latter, it is crucial that the measured intensities are equal to the true intensities. Some reduction in intensity due to defocus can be compensated for using defocus corrections, but for samples containing coarse grains, the further development of measurement techniques is necessary

Crystal orientation analysis of rolled sheet material by pole figure measurement

Metals and ceramics are used in various fields of engineering endeavor including buildings, airplanes,
automobiles, etc. In almost all of these applications the materials are polycrystalline and have a degree of
texture, i.e. crystal orientation. The crystal orientation is typically derived as a result of materials processing
stages such as forming and/or heat treatments. The crystal orientation can have a profound effect on thermal,
electrical and mechanical properties. Hence analysis of the crystal orientation is crucial for controlling
material properties. Crystal orientation can be determined from pole figures obtained by X-ray diffraction.
Furthermore, from the analysis by the Crystallite Orientation Distribution Function (ODF) method, the volume
fraction of the crystal orientation including other multiple orientations can be quantitatively obtained. In this
example, the pole figure of Cu rolled sheet was measured and the volume fraction of crystal orientation was
calculated.

Characterization of a Next-Generation Magnetic Recording Media (FePt) by In-Plane X-ray Diffraction

As next-generation ultrahigh-density magnetic recording media, granular thin films in which metal microparticles are dispersed have been a focus of attention. Among these films, the regular phase (tetragonal crystal) of FePt has a
particularly high magnetic anisotropy as well as good corrosion and oxidation resistances, so it is expected that it will be applied to actual devices. However, the irregular phase (cubic crystal) is created at the same time, depending on the filmforming conditions. For this reason, a technique to distinguish these crystalline phases at the nanoparticle and thin film level is required. Using the in-plane X-ray diffraction method, in which X-rays are irradiated on the surface of a thin film sample at a glazing angle to study the regular structure (crystal structure) in the in-plane direction, it is possible to identify the crystalline phase even for ultra-thin films of only a few nm in thickness. It is also possible to analyze the sample in the depth direction by changing the incident angle of X-rays entering the sample surface.

Quantification of trace crystal polymorph components using a high-speed 1-dimensional detector

Materials with the same chemical formula but different crystal structures are called crystal polymorphs. Since an X-ray diffraction profile depends on the crystal structure of the measured material, X-ray diffraction measurement is used to evaluate crystal polymorphs. Here we show an example in which a trace component of anatase (TiO2) contained in titanium oxide with a rutile (TiO2) structure, sold commercially as a reagent, was evaluated with the standard addition method by using a high-speed 1-dimensional detector.

Analysis of powder crystal structures of organic crystals using a high-resolution convergent beam optical system

Previously, it was typical to conduct crystal structure analysis using the single crystal method. However, analysis of crystal structure using the single crystal method is difficult in the case of samples for which it is hard to produce single crystals, and samples for which crystal growth is difficult even if single crystals can be produced. In recent years, the precision of powder X-ray diffractometers has been improving, and thus it is becoming possible to conduct crystal structure analysis using powder samples. Here we show an example where a powder sample was measured, and structural analysis was conducted based on the obtained diffraction pattern.

Analysis of a stony-iron meteorite using a HyPix-3000 multi-dimensional detector

A stony-iron meteorite is like a single crystal. When using 0- or 1-dimensional detectors, only a few diffraction peaks are observed. In this situation, identification of crystalline phases cannot be conducted. Therefore, a stony-iron meteorite was analyzed using the multi-dimensional detector, HyPix-3000, which has an effective detection area for the identification of crystalline phases.

LOQ of Trace Impurities in active pharmaceutical ingredients via the DD Method

Quantification of a trace amount of polymorphic impurities is critical especially in the quality control of Active
Pharmaceutical Ingredients (APIs). Conventional quantitative analysis by X-ray diffraction (XRD) requires
calibration curve preparation, reference intensity ratio (RIR) or crystal structure (Crystallographic Information
File, CIF). However, the materials of APIs are often missing from the database. Therefore, their quantification
is not straightforward. Rigaku have developed a novel quantitative analysis method called “Direct Derivation
(DD)” that requires only XRD data and chemical formula(1)- (3). Here, quantitative analysis of trace amounts of
the hydrate phase of API is performed using the DD method and the limit of quantification (LOQ) is calculated.

Structure determination of ferroelectric nano-powder by PDF analysis

Ferroelectric BaTiO3 (BT) is widely used as a capacitor material. The ferroelectricity of BT is strongly related to its
tetragonal crystal structure, but when the particle size becomes less than several tens of nanometers, the structure
exhibits cubic symmetry and the ferroelectricity disappears. A structural model where the central core is tetragonal and the outer shell is made of a cubic crystal has been proposed for BT. In general, the crystal structure of powder materials is determined by Rietveld analysis of the X-ray diffraction profile. However, it has been reported that the tetragonality (i.e., the c/a ratio, where a and c are the lattice constants) of BT approaches 1 as the particle size decreases, making it difficult to determine whether the crystal structure is tetragonal and/or cubic by Rietveld analysis only. Recently, many researchers have utilized PDF analysis (atomic Pair Distribution Function, G (r)). Since G(r) provides information on the probability of atoms being located at a distance “r” from each other, even a crystalline material showing the smallest tetragonality can be analyzed considering the symmetry of the local structure.

Operando measurement of Li ion battery positive electrode

Lithium ion secondary batteries are widely used in small portable devices such as mobile phones. Research
and development of lithium ion batteries for use in automobiles and larger machines is an active field. To
develop lithium ion secondary batteries with high capacity, high stability and long life, it is essential to evaluate
the stability of the positive electrode material during the charge/discharge process. Operando X-ray diffraction
measurements using an attachment that reproduces the charge/discharge environment and a 2D detector
that can perform high-speed measurements enables detailed observation of crystal phase changes while a
battery is in use, making it suitable for studying battery performance and life.

Quantitative analysis of anhydrite

Anhydrite or anhydrous calcium sulfate (CaSO4) is an important naturally-occurring compound found in many limestone formations and karst topography. This material has recently gained more significance to the cement industry as a substitute for gypsum—calcium sulfate dihydrate (CaSO4·2H2O). Anhydrite shows great efficacy as a cement setting retardant. This allows valuable time for other phases to form which enhances the cement’s tensile properties.

Quantification of Zeolite phases

Zeolites are commonly used in a vast variety of industrial applications, including environmental clean-up, petroleum cracking, filtering/separations and cation exchange. These materials can be mined from natural sources or can be commercially synthesized. A basic structure of five silicon and aluminum tetrahedra result in a cage-like structure with large open spaces or “pores”. These pores have charged regions which attract or exchange cations. For effective activity and specific cation incorporation, the zeolites need to be very specific and pure

Quality control in industrial processes with phase identification

Ensuring quality control can be a daunting task in industrial processes. The key to a quality product is to maintain that quality throughout the entire process and having the appropriate materials is essential to this accomplishment. The wrong materials could alter the properties of the desired product. It could even change the product and everyone would certainly want the finished product to be able to function with its desired task

Phase identification in the oil drilling industry

The oil drilling industry can encounter a wide variety of samples, including rocks, scales, cements, cuttings, and muds throughout the drilling process. X-ray diffraction (XRD) is an essential tool for phase identification analysis of these commonly identified solids in the oil field

General XRD phase/composition identification analysis

General X-ray diffraction phase/composition identification will distinguish the major, minor, and trace compounds present in a sample. The data usually includes mineral (common) name of the substance, chemical formula, crystalline system, and reference pattern number from the ICDD International database.

Fast phase analysis of mineral powders

X-ray diffraction (XRD) is an effective method for determination of the phase composition of unknown crystalline and amorphous materials. The analysis is performed by comparing diffraction peak positions and intensity values with the reference patterns of known compounds maintained in the ICDD Powder Diffraction File (PDF). Routine characterization is completed quickly with a minimum of operator involvement. Subsequent analyses, including quantitative analysis of identified phases, are easily accomplished

Quantitative analysis of a 4-component sample using a benchtop X-ray diffractometer

In the past, quantitative analysis with X-ray diffractometry was performed using calibration curves, but due to the
progress of computers and analysis software, quantitative analysis using the WPPF (Whole Powder Pattern Fitting)
method has now come into wide use. In the WPPF method, profile fitting is performed over a comparatively broad
angular range, based on information involving the crystal system and lattice constants. Since diffraction intensity can be refined at the same time as the diffraction angle, quantitative analysis can be done without the need for calibration curves.