Experimental Determinations of the Coherent Scattering Domain Size Distribution of Natural Mica-Like Phases with the Warren-Averbach Technique

Lanson, Bruno

doi:10.1346/ccmn.1994.0420418

Cited by 17 publications

(10 citation statements)

References 27 publications

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“…6,[12][13][14] This analysis continues to be applied to scattering from metals and superconductors, [15][16][17][18][19][20][21][22][23] ceramics, 24,25 and other materials. 26 These systems tend to have large CDDs and relatively small, unambiguous scattering backgrounds as compared to most polymers. In these materials, corrections for instrumental effects are the primary difficulty and erroneous background subtraction is a secondary concern limiting the final accuracy of extracted quantities.…”

Section: Introductionmentioning

confidence: 99%

Diffraction Line-Shape Analysis of Poly(3-dodecylthiophene): A Study of Layer Disorder through the Liquid Crystalline Polymer Transition

et al. 1999

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The nature of the structural ordering within semicrystalline poly(3-dodecylthiophene) films has been analyzed using a Warren-Averbach line-shape analysis which includes up to five orders of the (h00) lattice reflections. This analysis yields a semiquantitative measure of the volume averaged crystallite sizes, the lattice parameter variations, and the disorder fluctuations. The progression of these quantities has been followed through a liquid crystal polymer (LCP) phase transition which occurs in the vicinity of 60 °C. The pronounced peak width narrowing of the low-order (h00) reflections, observed on heating, is found to be essentially uncorrelated with a theorized annealing-induced increase in average crystallite size. The major contribution to this narrowing arises from systematic variations in the microscopic heterogeneities and fluctuations. Moreover, we observe an anomalously large increase in the higherorder (h00) (h ) 3-5) peak widths at temperatures spanning that of the thermotropic LCP transition. This effect is found to be strongly correlated with a maximum in the disorder fluctuations, and this relationship suggests an underlying mechanism for the nature of the LCP transition.

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Section: Introductionmentioning

confidence: 99%

Diffraction Line-Shape Analysis of Poly(3-dodecylthiophene): A Study of Layer Disorder through the Liquid Crystalline Polymer Transition

et al. 1999

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“…Recently, Lanson and Kubler (1994) used the same technique and the same software to analyze profiles of basal reflections for a large collection of illites and IS. For some samples they found a strong disagreement among mean thicknesses of CSDs obtained by Fourier analysis and by other techniques.…”

Section: Introductionmentioning

confidence: 99%

XRD Measurement of Mean Thickness, Thickness Distribution and Strain for Illite and Illite-Smectite Crystallites by the Bertaut-Warren-Averbach Technique

Drits

1998

Clays and clay miner.

122

113

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A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949(Bertaut , 1950Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions for calculated and experimental XRD patterns of illites and illite-smectites (I-S). The method almost exactly recovers CSD thickness distributions for calculated illite XRD patterns. Natural I-S samples contain swelling layers that lead to nonperiodic structures in the c* direction and to XRD peaks that are broadened and made asymmetric by mixed layering. Therefore, these peaks cannot be analyzed by the BWA method. These difficulties are overcome by K-saturation and heating prior to X-ray analysis in order to form 10-,~ periodic structures. BWA analysis yields the thickness distribution of mixed-layer crystals (coherently diffracting stacks of fundamental illite particles). For most I-S sampies, CSD thickness distributions can be approximated by lognormal functions. Mixed-layer crystal mean thickness and expandability then can be used to calculate fundamental illite particle mean thickness. Analyses of the dehydrated, K-saturated samples indicate that basal XRD reflections are broadened by symmetrical strain that may be related to local variations in smectite interlayers caused by dehydration, and that the standard deviation of the strain increases regularly with expandability. The 001 and 002 reflections are affected only slightly by this strain and therefore are suited for CSD thickness analysis. Mean mixed-layer crystal thicknesses for dehydrated I-S measured by the BWA method are very close to those measured by an integral peak width method.

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“…Similar differences were found for illite–muscovite from pelitic rocks by Merriman et al . (1990 ), Lanson & Kübler (1994), Jiang et al . (1997 ), Li et al .…”

Section: Discussionmentioning

confidence: 99%

“…Accurate determination of the absolute values of mean crystallite size and lattice strain by analyses of XRD line profiles is hindered by numerous factors ( Lanson & Kübler, 1994; Árkai et al ., 1996, 1997; Warr, 1996; Drits et al ., 1997 ). Nevertheless, the results obtained by the Scherrer and Voigt methods ( Tables 5–7) confirm that the apparent mean crystallite size of chlorite increases with increasing grade.…”

Section: Discussionmentioning

confidence: 99%

Comparison of diagenetic and low‐grade metamorphic evolution of chlorite in associated metapelites and metabasites: an integrated TEM and XRD study

Árkai

Mata

Giorgetti

et al. 2000

Journal Metamorphic Geology

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Chlorite is a common sheet silicate that occurs in various lithologies over a wide grade range involving diagenesis and low‐grade metamorphism. Thus, the reaction progress of chlorite offers a unique opportunity for direct correlation of zonal classification of metasedimentary rocks based on illite crystallinity with metabasite mineral facies. To provide such correlation, chlorite crystallinity indices, apparent mean crystallite sizes and lattice strains, crystallite size distributions and compositions of chlorite from coexisting metapelites and metabasites were determined by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), analytical electron microscopy (AEM) and electron microprobe (EMP) methods. Samples were from Palaeozoic and Mesozoic formations of the Bükkium (innermost Western Carpathians, Hungary) that underwent Alpine (Cretaceous) orogenic metamorphism. Metapelites range in grade from late diagenesis to epizone, whereas metabasites vary from prehnite–pumpellyite through pumpellyite–actinolite to greenschist facies. Despite significant differences in composition, mineral assemblages and textures, reaction progress, as measured in part by chlorite crystallinity, in metapelites paralleled that in metabasites. Chlorite crystallinity and mean crystallite size increase and the proportion of mixed layers in chlorite decreases, whereas the calculated lattice strain does not change significantly with increasing metamorphic grade. Similar trends, but (especially at higher grades) significant differences, were found in mean crystallite size values using various methods for XRD line profile analyses. The increase in crystallite size with increasing grade was demonstrated also by direct TEM measurements on ion‐milled whole‐rock samples, but with a larger scatter of data at higher grades. In spite of the different kinds of mixed layering in chlorite (Mg‐rich smectitic, mostly random, local corrensite‐like units in metabasites, and Fe‐rich berthierine and dioctahedral smectite in metapelites), XRD‐calculated and TEM‐measured parameters were found to be reliable tools for measuring reaction progress and metamorphic grade of the same degree in both lithotypes.

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Experimental Determinations of the Coherent Scattering Domain Size Distribution of Natural Mica-Like Phases with the Warren-Averbach Technique

Cited by 17 publications

References 27 publications

Diffraction Line-Shape Analysis of Poly(3-dodecylthiophene): A Study of Layer Disorder through the Liquid Crystalline Polymer Transition

Diffraction Line-Shape Analysis of Poly(3-dodecylthiophene): A Study of Layer Disorder through the Liquid Crystalline Polymer Transition

XRD Measurement of Mean Thickness, Thickness Distribution and Strain for Illite and Illite-Smectite Crystallites by the Bertaut-Warren-Averbach Technique

Comparison of diagenetic and low‐grade metamorphic evolution of chlorite in associated metapelites and metabasites: an integrated TEM and XRD study

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