Particle orientation distributions and stacking arrangements in size-fractionated montmorillonite measured by neutron and X-ray diffraction

Author(s):  
P. L. Hall ◽  
R. Harrison ◽  
M. H. B. Hayes ◽  
J. J. Tuck ◽  
D. K. Ross
Clay Minerals ◽  
1966 ◽  
Vol 6 (3) ◽  
pp. 127-142 ◽  
Author(s):  
R.M. Taylor ◽  
K. Norrish

AbstractUsing X-ray techniques, the orientation distributions of crystal planes in laboratory prepared and naturally occurring aggregates were measured. A small specimen was mounted on the axis of a goniometer and the diffracted intensity measured as the specimen was rotated. Mo radiation was used to reduce the absorption effects. A mathematical relation between the distribution of particles and the distribution of crystal planes was derived for platy and fibrous particles in flake-like and rod-shaped specimens.When diffracted intensities of the 001 reflection of several different kaolinites were corrected for the degree of orientation in the respective specimens, a constant value was obtained. This would enable quantitative diffraction analyses to be made without the large errors that can be introduced by orientation effects. The degree of particle orientation achieved appeared to be more dependent on particle morphology than on the method of sample preparation or formation.


2017 ◽  
Vol 898 ◽  
pp. 1431-1437
Author(s):  
Hong Yang Shao ◽  
Kan Zhang ◽  
Yi Dan Zhang ◽  
Mao Wen ◽  
Wei Tao Zheng

The δ-NbN thin films with different thickness have been prepared by reactive magnetron sputtering at different deposition time and exhibited alternating textures between (111) and (200) orientations as a function of thickness. In addition, the grain size, peak position, morphology, residual stress and orientation distributions of the deposited films were explored by X-ray diffraction, low-angel X-ray reflectivity, scanning electron microscopy and surface profiler. The film deposited at 300 s showed a (111) preferred orientation, changing to (200) preferred orientation at 600 s, and exhibited alternating textures between (111) and (200) preferred orientations. With further increasing deposition time, in which (200) peak position and the full width at half maximum of (111) peak also displayed a trend of alternating variation with varying deposition time. The intrinsic stress for δ-NbN films calculated by Stoney equation alternately changed with alternating textures, in which (111) orientation always takes place at relatively high intrinsic stress state and vice versa. Meanwhile, the film with (111) preferred orientation showed higher density than (200) preferred orientation. The film deposited at 4800 s owned a mixed texture of (111) and (200), showing an anisotropy distribution of (111)-oriented and (200)-oriented grains, while film deposited at 7200 s owned a strong (200) texture, displaying an isotropy distribution of (200)-oriented grains. The competitive growth between (111)-oriented and (200)-oriented grains was responsibility for alternating texture.


2016 ◽  
Vol 108 (18) ◽  
pp. 181902 ◽  
Author(s):  
Bingxiao Zhao ◽  
Omar Awartani ◽  
Brendan O'Connor ◽  
Mohammed A. Zikry

1986 ◽  
Vol 1 (3) ◽  
pp. 240-243 ◽  
Author(s):  
Briant L. Davis

AbstractHighly uniform fine powder sample layers may be prepared for X-ray diffractometry by aerosol suspension and collection on glass fiber filter substrates. A tubular aerosol suspension chamber (TASC) has been fabricated for this purpose. Essential components include a 500 ml gas buret, 4.7-cm filter cassette, rotameter, and rotary pump. Aerosol particles are generated within the TASC buret by convection within a fluidized bed of glass beads mixed with the sample. Exceptional uniformity of load and randomness of particle orientation has been demonstrated for samples prepared with this system. For quantitative analytical work accurate intensities may be obtained using corrections to raw intensities based on fundamental sample and filter properties.


Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 89-98 ◽  
Author(s):  
N. J. Elton ◽  
L. F. Gate ◽  
J. J. Hooper

AbstractX-ray diffraction (XRD), infra red (IR) spectroscopy, gloss goniophotometry and stylus profilometry were used to investigate the alignment of kaolinite applied as a thin coating on a polyester film substrate. The principles and applicability of the analytical methods are reviewed and discussed in the context of a kaolinite coating. X-ray diffraction and transmission IR were used to measure kaolinite misalignment and orientation distribution in the coating. Transmission IR measures the coating bulk; XRD data are surface biased, but contain contributions from the bulk. Attenuated total reflectance-IR (ATR-IR) provides a direct measure of kaolinite alignment within ~1 µm of the coating surface and also allows an assessment of surface smoothness. Gloss goniophotometry and contact profilometry measure surface microroughness and macroroughness, respectively, rather than kaolinite particle orientation. However, the properties of roughness and orientation are related. Bulk and surface texture are not necessarily correlated and a combined approach using both bulk and surface sensitive techniques is required for a full understanding of coating structure.


Clay Minerals ◽  
1982 ◽  
Vol 17 (4) ◽  
pp. 401-408 ◽  
Author(s):  
D. Minichelli

AbstractThe method described uses external standard mixtures, both natural and artificial. Variations in degree of structural order between standard and analyte mineral are taken into account. ‘Amorphous’ materials in standard mixtures are simulated by alkali-boron-silicon glasses. Variations in response of the X-ray equipment with time are assessed by running a standard multiphase mixture. Strict control is exercised on particle orientation, and thermal treatments are used to separate overlapping reflections in the low-2θ region.


2014 ◽  
Vol 70 (a1) ◽  
pp. C726-C726
Author(s):  
Aline Dellicour ◽  
Alain Pautrat ◽  
Bénédicte Vertruyen ◽  
Mark Rikel ◽  
Luca Lutterotti ◽  
...  

Bi2Sr2CaCu2O8+δ HTSC superconductor is characterized by a very strong normal-state resistivity anisotropy, with ρc/ρab typically above 10E4. The aim of this study is to use Quantitative Texture Analysis from x-ray diffraction measurements to estimate the orientation effect on the anisotropic macroscopic resistivity in melt-cast bulk Bi2Sr2CaCu2O8+δ superconductors. Our approach uses the geometric mean [1] of the single crystal resistivity tensor weighted by the Orientation Distribution Function (ODF) to quantitatively estimate the macroscopic resistivity tensor of the samples. The ODF is obtained from x-ray Combined Analysis [2], using the E-WIMV algorithm of the MAUD software. The GMA applies to the rank-two resistivity tensor of the orthorhombic space group considered tetragonal due to the small difference of a- and b-axes of the phase, with only two independent tensor components. We relate a relatively good agreement between measured and calculated macroscopic anisotropic resistivity ratios. Even with ρc/ρab between 10E4 and 10E5 for Bi2212 at room temperature in single crystals [3], we experiment macroscopic ratio in our bulk samples of around only 2. This small ratio is explained by the weak planar- or fiber-like (Figure) texture achieved in the melt-cast samples, characterized by maxima of orientation distributions not larger than 10 mrd. Calculated resistivities, based on homogeneous crystallites, perfect grain boundaries and no secondary phases, are 10 times larger than the observed ones. This suggests that the observed minor phases positively affect conductive pathways between grains. Calculated and measured anisotropic resistive ratios are coherent with one another, and Combined Analysis gives good predictions of these former.


Clay Minerals ◽  
1971 ◽  
Vol 9 (1) ◽  
pp. 47-70 ◽  
Author(s):  
J. S. Tchalenko ◽  
A. D. Burnett ◽  
J. J. Hung

AbstractThe spatial arrangement of platy particles in a clay is defined by an orientation ratio which can be derived analytically from optical birefringence as well as from X-ray diffraction data. Measurements on kaolin slurries consolidated by increasing loads were used to verify that orientation ratios obtained experimentally by these two methods are in fact equivalent. In contrast it was found that particle orientation cannot be assessed objectively from electronmicrographs alone. A combined optical-X-ray study of two natural clays (London Clay and Lias Clay) revealed that the kaolinite crystals are oriented only slightly more than the illite crystals, and showed that the correspondence between optical and X-ray measurements is also valid for natural clays.


2005 ◽  
Vol 38 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Emmanuel Guilmeau ◽  
Daniel Chateigner ◽  
Jacques Noudem ◽  
Ryoji Funahashi ◽  
Shigeru Horii ◽  
...  

Orientation distributions of cobaltite thermoelectric and polyphased bismuth-based cuprate superconducting textured materials are determined from neutron and X-ray diffraction analysis. Curved position-sensitive detectors coupled to a tilt-angle (χ) scan enable the treatment of the whole diffraction pattern using the combined Rietveld–WIMV–Popa algorithm. The textures of three phases of superconducting compounds are determined. The critical current densities, measured for four samples, are strongly dependent on the calculated texture strengths, crystallite sizes and phase ratios. For the cobaltite compounds, a comparison between X-ray and neutron analysis shows the advantages of the latter technique for avoiding the limitations of the X-ray analysis with respect to the defocusing effect. The results highlight the necessity and efficiency of the combined approach for a quantitative texture analysis of complex materials and exemplify the texture–anisotropic physical properties relationship for a better understanding and design of improved bulk superconducting and thermoelectric materials.


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