MULTI-PEAK MATCH INTENSITY RATIO METHOD OF QUANTI-TATIVE X-RAY DIFFRACTION PHASE ANALYSIS

A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory.

Fitting Full X-Ray Diffraction Patterns for Quantitative Analysis: A Method for Readily Quantifying Crystalline and Disordered Phases

Fitting of full X-ray diffraction patterns is an effective method for quantifying abundances during X-ray diffraction (XRD) analyses. The method is based on the principal that the observed diffraction pattern is the sum of the individual phases that compose the sample. By adding an internal standard (usually corundum) to both the observed patterns and to those for individual pure phases (standards), all patterns can all be normalized to an equivalent intensity based on the internal standard intensity. Using least-squares refinement, the individual phase proportions are varied until an optimal match is reached. As the fitting of full patterns uses the entire pattern, including background, disordered and amorphous phases are explicitly considered as individual phases, with their individual intensity profiles or “amorphous humps” included in the refinement. The method can be applied not only to samples that contain well-ordered materials, but it is particularly well suited for samples containing amorphous and/or disordered materials. In cases with extremely disordered materials where no crystal structure is available for Rietveld refinement or there is no unique intensity area that can be measured for a traditional RIR analysis, full-pattern fitting may be the best or only way to readily obtain quantitative results. This approach is also applicable in cases where there are several coexisting highly disordered phases. As all phases are considered as discrete individual components, abundances are not constrained to sum to 100%.

AN INCREMENTAL METHOD OF X-RAY DIFFRACTION QUANTITATIVE PHASE ANALYSIS OF SAMPLESCONTAINING AMORPHOUS MATERIAL

A new method for quantitative X-ray diffraction phase analysis of a powder misture has been developed according to Popovic's doping method. The weight fraction of amorphous material in the analysed sample is obtained. For a multicomponent system in which (n-2) pure phases are added into an n-phase compnent sample and theweight fractions of all n phases can be determined by the method. The test results of confirmation agree well with the theory.

A SOLUTION OF MINIMUM NORM FOR QUANTITATIVE PHASE ANALYSIS BY STANDARDLESS X-RAY DIFFRACTION

A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus,The criterion of standardless X-ray diffraction analysis was suggested,so as to separate the diffraction pattern of every phase from that of sample.The optimal solution could be obtained by the least squares regression.

A SOLUTION OF MINIMUM NORM FOR QUANTITATIVE PHASE ANALYSIS BY STANDARDLESS X-RAY DIFFRACTION

A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus.The criterion of standardless X-ray diffraction analysis was suggested,so as to separate the diffraction pattern of every phase from that of sample.The optimal solution could be obtained by the least squares regression.

THE DEGREE OF CRYSTALLINITY OF MULTICOMPONENT POLYMERS BY X-RAY DIFFRACTION ANALYSIS

Based on the X-ray scattering intensity theory,the correction factors of the degree of crystallinity formulae of the multicomponent polymers have been clearly defined.The formula of degree of erystallinity of the multicomponent polymers was derived in terms of the WAXD theory ahd improved graphic multipeak resolution methods.The results calculated are compatible with the density measurement.

Investigation of Changes in the Fine Structure of Graphitizing Carbon Materials during Heat Treatment by X-Ray Diffraction Analysis

The properties of synthetic graphite materials, widely used in advanced fields, are determined by their structure, which is formed in the process of high-temperature (~2500°C) heat treatment. The fine structure of a graphitizing carbon material based on petroleum coke containing 1.3 wt% S at various stages of graphitization was studied by X-ray diffraction analysis. Some of the samples contained the addition of dispersed Fe2O3. It is shown that the heat-treated material in the range 1200°C - 2600°C is heterogeneous, its component composition is determined by the processing temperature and the presence of Fe2O3 additive. The observed dependence of the component composition on the heat treatment temperature suggests that the process of graphitization of the carbon material, apparently, develops through a number of metastable states.

AN EXTERNAL STANDARD METHOD OF QUANTITATIVE PHASE ANALYSIS OF THE SAMPLE CONTAINING AN AMORPHOUS PHASE BY X—RAY DIFFRACTION

A new method of the quantitative phase analysis of the sample containing an amorphous phase or a standardless phase by X-ray diffraction is proposed in the paper. The addtion of a reference phase or some analytical phase to the analyzed sample is not required in this method and the experimental results are satisfactory.

X-Ray Analysis by Williamson-Hall and Size-Strain Plot Methods of ZnO Nanoparticles with Fuel Variation

In this paper, a simple and facile surfactant assisted combustion synthesis is reported for the ZnO nanoparticles. The synthesis of ZnO-NPs has been done with the assistance of non-ionic surfactant TWEEN 80. The effect of fuel variations and comparative study of fuel urea and glycine have been studied by using characterization techniques like X-ray diffraction (XRD), transmission electron microscope (TEM) and particle size analyzer. From XRD, it indicates the presence of hexagonal wurtzite structure for ZnO-NPs. Using X-ray broadening, crystallite sizes and lattice strain on the peak broadening of ZnO-NPs were studied by using Williamson-Hall (W-H) analysis and size-strain plot. Strain, stress and energy density parameters were calculated for the XRD peaks of all the samples using (UDM), uniform stress deformation model (USDM), uniform deformation energy density model (UDEDM) and by the size-strain plot method (SSP). The results of mean particle size showed an inter correlation with W-H analysis, SSP, particle analyzer and TEM results.

X-Ray Diffraction, Electron Paramagnetic Resonance and Optical Absorption Study of Bauxite

The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques.

DATA PROCESSING OF UNIVERSAL QUANTITATIVE METHOD IN STANDARDLESS X-RAY PHASE ANALYSIS

Accuracy of coeffcient A_(isp) is related to the reference phase chosen during analysis. The cri- terion of choosing reference phase which may minimize the error of A_(isp) was deduced. The optimum results could be obtained by using the method of least squares if the number of sam- pies for analysis is more than the phase in samples. The procedure presented here is satisfacto- ryfor ordinary phase analysis.

Soil Clay Mineralogical Phase Analysis of Ganges Floodplain Soils by XRD and XRF

Soil minerals study is vital in terms of investigating the major soil forming compounds and to find out the fate of minor and trace elements in soils. It is also essential for the soil-plant interaction purpose. To identify soil mineral phases especially clay minerals, X-ray diffraction (XRD) has been a popular technique. The clay mineralogical information of soils in Bangladesh is limited, especially in Ganges flood plain region (Agro Ecological Zone (AEZ) 12 and 13). Therefore, to overcome this limitation, in this study, we performed XRD analysis of <2 mm fractions soil samples of AEX 12 and 13. However, identifying mineralogical phases by XRD in <2 mm fractions soils is not so straight-forward due to many practical problems. We fully matched only two mineralogical phases in all the soil samples which is quartz and potassium-Aluminum-Silicate. However, the full XRD peaks indicate that more minerals are also present, but due to heterogeneity of soils samples, it is difficult to find other minerals phases by only XRD peak of <2 mm fractions. Therefore, to find more information about mineralogical phases, we performed XRF analysis that provides the elemental composition of minerals phase as oxide. XRF analysis indicated the presence of secondary minerals like illite and chlorite. The presence of high percentage Fe oxide not only indicated the iron mineral phase (goethite and ferrihydrite) but also indicated iron rich high charge smectite minerals (beidellite). The presence of iron rich smectite minerals in the Ganges sediments reported in several previous studies. Thus, we concluded that only XRD in <2 mm fractions of soils is not adequate to identify the mineralogical phases of soil samples. Others analyses like XRF, XRD in <2 μm fractions will be necessary to locate an entire image of soil mineralogical phases.

X-Ray Powder Diffraction: Why Not Use CuKβ Radiation?

CuKβ radiation with a wavelength of λ = 1.3923 ? is recommended for crystal structure determination from X-ray powder diffraction using the Rietfeld method. A highly sensitive image plate detector is able to collect enough intensity to record a brilliant X-ray powder pattern in a reasonable time, compared to CuKα1 radiation used today. Especially atomic displacement coefficients could be determined more precisely with the much greater number of reflections recorded. A double-radius Guinier camera attached to a micro-focus rotating anode tube ensures increased brilliance besides high resolution. A simple construction specification is presented to make smart cylindrically bent Ge(111) or Si(111) X-ray monochromators that deliver focused CuKβ radiation. The highly linear response of image plate detectors allows removing of fluorescence radiation simply as background of the pattern. The proposed equipment is a cost-efficient alternative to a liquid gallium-metal-jet X-ray source with maximum power load and a similar wavelength of λ(GaKα1) = 1.34013 ?.

A New Method for Clay Mineral Analysis and Its Application in Geology

X-ray diffraction (XRD) peaks in a low-angle diffraction section of clayminerals, especially those of authigenic origin, have broadening and tailing features in shape.Using the five basic parameters, peak position, peak height, width, shape coefficient and asymmetry,to describe an XRD peak is more accurate, comprehensive and integrated than using only 3 of them,position, height and width. Following the concept of the five basic parameters of an XRD peak, theprogram Decoform proposed in this study provides more information in mineralogical analyses byfitting actual XRD profiles. In combination with the HW-IR plot, Decoform can he systematically andaccurately used in the comprehensive analyses of crystallinity, domain size, lattice strain andquantitative phase. It is also of value for the geological investigations of diagenesis,metamorphism, basin maturity, structural stress field and so on.

Crystallographic Characteristic of Intermetallic Compounds in Al-Si-Mg Casting Alloys Using Electron Backscatter Diffraction

The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5（Fe, Mn）3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope（OM）, scanning electron microscope（SEM）, energy dispersive X-ray spectrometer（EDS）, electron backscatter diffraction（EBSD） and X-ray powder diffraction（XRD）. The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P6_2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys.

Analysis of the inhomogeneous barrier and phase composition of W/4H-SiC Schottky contacts formed at different annealing temperatures

The electrical characteristics of W/4H-SiC Schottky contacts formed at different annealing temperatures have been measured by using current-voltage-temperatures（I-V -T） and capacitance-voltage-temperatures（C-V -T） techniques in the temperature range of 25℃-175℃. The testing temperature dependence of the barrier height（BH） and ideality factor（n） indicates the presence of inhomogeneous barrier. Tung＇s model has been applied to evaluate the degree of inhomogeneity, and it is found that the 400℃ annealed sample has the lowest T0 of 44.6 K among all the Schottky contacts. The barrier height obtained from C-V -T measurement is independent of the testing temperature, which suggests a uniform BH.The x-ray diffraction（XRD） analysis shows that there are two kinds of space groups of W when it is deposited or annealed at lower temperature（≤500℃）. The phase of W2C appears in the sample annealed at 600℃, which results in the low BH and the high T0. The 500℃ annealed sample has the highest BH at all testing temperatures, indicating an optimal annealing temperature for the W/4H-SiC Schottky rectifier for high-temperature application.

Structural Analysis of Eu_2Mn_(2/3)Ta_ 4/3O_7 with a Pyrochlore-Related Structure

Eu 2Mn 2/3Ta 4/3O 7 specimen was synthesized from Eu 2O 3, MnO and Ta 2O 5 in a reducing atmosphere. Structure analysis was carried out by Rietveld method from X-ray diffraction data. The X-ray diffraction profile calculated with monoclinic C2/c model was in a good agreement with the observed X-ray diffraction patterns since several small peaks of super lattice could be also assigned with C2/c symmetry in addition to fundamental reflection peaks. Eu 2Mn 2/3Ta 4/3O 7 has two kinds of distorted (Mn, Ta)O 6 octahedra and HTB layers, which deviates from the regular forms. Europium atoms coordinate to eight or seven oxygen atoms and lead to two kinds of polyhedra, EuO 8 and EuO 7 in this compound.

Characterization of the Thermo-Microstructural Analysis of Raffia Palm Fibers Proposed for Roofing Sheet Production

Raffia fibres are made from fibrous branches and leaves of Raffia palm. The membrane on the underside of each individual frond leaf is taken off to create a long thin fiber. They are usually waste materials which cause a great environmental degradation. The characterization of Raffia palm fibers/ particles was investigated through X-ray diffractometer (XRD), thermogravimetric analysis (TGA/DTA), Fourier transform infrared spectrometry (FTIR), Scanning electron mi croscope with energy dispersive spectrometer (SEM/EDS) and Atomic force microscope (AFM). The various results obtained are equivalent to those of other agro-waste materials generally used in roofing sheets composites production. Hence, this work shows that Raffia palm fibers/particles can be a useful material for cement mortar composites production which can be used for production of roofing sheets.

Spectroscopic Analysis of Expired and Pure Melmet

Spectroscopy is a perfect analyzer to find the elements of all matter. The application of spectroscopy has been used to interpret the effect of antibiotics and other medicines after its life duration. This has been studied by using the diabetics tablet melmet, expired for an year, to visualize the changes physically and chemically [1-3]. It has been observed that the occurrence of changes in color and reduction of smell and also the formation of new peaks and shift by XRD and UV, FTIR characterization respectively [4].

硼砂煅制工艺优化及质量评价

目的 优化硼砂煅制工艺,并对其进行质量评价。方法 以铺设厚度、煅制温度、煅制时间为影响因素,失水率、蓬松度、粉碎率、四硼酸钠含量为评价指标,星点设计-效应面法优化硼砂煅制工艺。采用扫描电镜(SEM)、热重分析(TG)、拉曼光谱、X射线衍射(XRD),比较硼砂煅制前后质量差异。结果 最佳条件为铺设厚度2 cm,煅制温度365℃,煅制时间100 min。煅制后,硼砂微观形态、成分组成、晶型结构发生变化,失去全部结晶水而转变为非晶体状态。结论 该方法稳定可行,可用于工业大批量生产煅硼砂。