Line Broadening Analysis Using FullProf*: Determination of Microstructural Properties

Rodríquez-Carvajal, Juan; Roisnel, Thierry

doi:10.4028/www.scientific.net/msf.443-444.123

Cited by 206 publications

(189 citation statements)

References 7 publications

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“…All samples have shown strain mainly directed along c. The peak shift parameter Sh was refined according to the expression 2θ shifted = 2θ Bragg + 2Sh d 2 tan θ × 10 −2 for reflections (h,k,l) with l = 4n. Although some values obtained during this work clearly differed from zero and thus provided evidence for the existence of stacking faults [21][22][23] this parameters will not be discussed in the text. The results (cell parameters, atomic displacement parameters, grain size, strain, Sh parameter) are summarized in Table 1.…”

Section: X-ray Powder Diffraction (Equipment and Analysis)mentioning

confidence: 99%

“…The following microstructure parameters were extracted from the data by conventional Rietveld analyses (program Fullprof.2k [21]): average crystallite size and anisotropic strain from diffraction line broadening, and peak shift parameter Sh (related to stacking faults [21][22][23]) from the displacements of certain groups of reflections (see below). The diffraction profiles (both instrumental and sample intrinsic) were modelled by using a Thomson-Cox-Hastings pseudo-Voigt function [21] (convolutions between Gaussian and Lorentzian components having different full widths at half maximum, FWHM) to simulate the peak shapes of both NaAlH 4 , Si and impurities phases when present. Structural parameters of the alanate structure were fixed at the values reported by Hauback et al [24]: space group I4 1 /a, Na in 4a (0, 1/4, 1/8), Al in 4b (0, 1/4, 5/8) and H in 16f (0.2372, 0.3836, 0.5469).…”

Section: X-ray Powder Diffraction (Equipment and Analysis)mentioning

confidence: 99%

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Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Gomes

Renaudin

Hagemann

et al. 2005

Journal of Alloys and Compounds

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The effects of milling and doping NaAlH 4 with TiCl 3 , TiF 3 and Ti(OBu n ) 4 , and of cycling doped NaAlH 4 have been investigated by infrared (IR) and Raman spectroscopy and X-ray powder diffraction. Milling and doping produce similar effects. Both decrease the crystal domain size (∼900Å for milled and ∼700Å for doped, as compared to ∼1600Å for unmilled and undoped NaAlH 4 ) and increase anisotropic strain (by a factor >2.5, mainly along c). They also influence structure parameters such as the axial ratio c/a, cell volume and atomic displacement amplitudes. They show IR line shifts by ∼15 cm −1 to higher frequencies for the Al-H asymmetric stretching mode ν 3 , and by ∼20 cm −1 to lower frequencies for one part of the H-Al-H asymmetric bending mode ν 4 , thus suggesting structural changes in the local environment of the [AlH 4 ] − units. The broad ν 3 bands become sharpened which suggests a more homogeneous local environment of the [AlH 4 ] − units, and there appears a new vibration at 710 cm −1 . The Raman data show no such effects. Cycling leads to an increase in domain size (1200-1600Å), IR line shifts similar to doped samples (except for TiF 3 : downward shift by ∼10 cm −1 ) and a general broadening of the ν 3 mode that depend on the nature of the dopants. These observations support the idea that some Ti diffusion and substitution into the alanate lattice does occur, in particular during cycling, and that this provides the mechanism through which Ti-doping enhances kinetics during re-crystallisation.

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Section: X-ray Powder Diffraction (Equipment and Analysis)mentioning

confidence: 99%

Section: X-ray Powder Diffraction (Equipment and Analysis)mentioning

confidence: 99%

Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Gomes

Renaudin

Hagemann

et al. 2005

Journal of Alloys and Compounds

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“…The refined lattice parameters werec ompared to those found in the literature [56,57] which showed that both materials maintained their structural characteristics after forming the nanocomposite. It is known that the polyaniline synthesis conditions interfere in their physical and chemical characteristics.…”

Section: Le Bail Methods Analysismentioning

confidence: 99%

“…The explicit formula of the intrinsic integralb readth using the SPH treatment of size broadening is given by [57]:…”

Section: Le Bail Methods Analysismentioning

confidence: 99%

Nanocomposite based on polyaniline emeraldine-base and α-Al₂O₃: A structural characterization

Sanches

Souza

Carvalho

et al. 2015

International Journal of Materials Research

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Nanocompositeb ased on polyaniline emeraldinebase and a -Al 2 O 3 :Astructural characterization Ac eramic-matrix nanocomposite based on polyaniline emeraldine base and aluminum oxide (PANI-EB/a -Al 2 O 3 ) was obtained by in-situ polymerization. X-ray diffraction pattern presented peaks related to bothmaterials. The level of crystallinity was estimated at about 53 %. The average crystallite sizes of PANI-EB and a -Al 2 O 3 werefound to be * 40 Åa nd 570 Å, respectively. Scanning electron microscopy showed polymerization over ceramic particles. Fourier-transform infrared spectroscopy suggested physical deposition. The electrical conductivity of the PANI-EB/aAl 2 O 3 nanocomposite was decreased by afactor of 80 when compared withthat of pure PANI-EB.Therefore, the polymeric reinforcementa nd the ceramicm atrix maintained their original structural features, but the electrical conductivity in the nanocomposite was reduced.

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“…72-0686) was refined by the Rietveld method with the FullProf.2k (v.5.40) program [14]. The microstructure of crystallites (average apparent crystallite size D, average maximum strain S) was defined within this Rietveld refinement procedure in terms of isotropic line broadening [15].…”

Section: Methodsmentioning

confidence: 99%

Mechanochemically driven amorphization of nanostructurized arsenicals, the case of β-As4S4

et al. 2018

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The amorphization is studied in mechanically activated b-As 4 S 4 using highenergy ball milling in a dry mode with 100-600 min -1 rotational speeds, employing complementary methods of X-ray powder diffraction (XRPD) related to the first sharp diffraction peak, positron annihilation lifetime (PAL) spectroscopy, and ab initio quantum-chemical simulation within cation-interlinking network cluster approach (CINCA). The amorphous substance appeared under milling in addition to nanostructurized b-As 4 S 4 shows character XRPD halos parameterized as extrapolation of the FSDPs, proper to near-stoichiometric amorphous As-S alloys. The structural network of amorphized arsenicals is assumed as built of randomly packed multifold cycle-type entities proper to As 4 S 4 network. The depressing and time-enhancing tendency in the PAL spectrum peak is direct indicative of milling-driven amorphization, associated with free-volume evolution of interrelated positron-and Ps-trapping sites. At lower speeds (200-500 min -1 ), these changes include Ps-to-positron trapping conversion, but they attain an opposite direction at higher speed (600 min -1 ) due to consolidation of b-As 4 S 4 crystallites. In respect of CINCA modeling, the effect of high-energy milling is identified as destruction-polymerization action on monomer cage-type As 4 S 4 molecules and existing amorphous phase, transforming them to amorphous network of triple-broken As 4 S 4 derivatives. These findings testify in a favor of ''shell'' kinetic model of solid-state amorphization, the amorphous phase continuously generated under speed-increased milling being identified as compositionally authentic to arsenic monosulfide, different in medium range ordering from stoichiometric As 2 S 3 .

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Line Broadening Analysis Using FullProf*: Determination of Microstructural Properties

Cited by 206 publications

References 7 publications

Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Nanocomposite based on polyaniline emeraldine-base and α-Al₂O₃: A structural characterization

Mechanochemically driven amorphization of nanostructurized arsenicals, the case of β-As4S4

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Line Broadening Analysis Using FullProf*: Determination of Microstructural Properties

Cited by 206 publications

References 7 publications

Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Effects of milling, doping and cycling of NaAlH4 studied by vibrational spectroscopy and X-ray diffraction

Nanocomposite based on polyaniline emeraldine-base and α-Al2O3: A structural characterization

Mechanochemically driven amorphization of nanostructurized arsenicals, the case of β-As4S4

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Nanocomposite based on polyaniline emeraldine-base and α-Al₂O₃: A structural characterization