A comparison between the Warren-Averbach method and alternate methods for X-ray diffraction microstructure analysis of polycrystalline specimens

Marinković, Bojan A.; Avillez, Roberto Ribeiro de; Saavedra, A.; Rizzo, F.

doi:10.1590/s1516-14392001000200005

Cited by 35 publications

(10 citation statements)

References 26 publications

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“…However, one must remember that the crystal structures of the γ phase and the ε phase are quite similar, and thus both of them have XRD reflections either in the same 2θ angels or very close to each other. The average grain size of both types of samples after annealing was determined to be around 30 nm using the Warren-Averbach method for XRD data (Marinkovic et al, 2001). In Fig.…”

Section: Crystal Structure Characterization Of the Sensing Layersmentioning

confidence: 99%

Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition

Leidinger

Huotari

Sauerwald

et al. 2016

J. Sens. Sens. Syst.

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Abstract. Pulsed laser deposition (PLD) at room temperature with a nanosecond laser was used to prepare WO 3 layers on both MEMS microheater platforms and Si/SiO 2 substrates. Structural characterization showed that the layers are formed of nanoparticles and nanoparticle agglomerates. Two types of layers were prepared, one at an oxygen partial pressure of 0.08 mbar and one at 0.2 mbar. The layer structure and the related gas sensing properties were shown to be highly dependent on this deposition parameter. At an oxygen pressure of 0.2 mbar, formation of ε-phase WO 3 was found, which is possibly contributing to the observed increase in sensitivity of the sensor material.The gas sensing performance of the two sensor layers prepared via PLD was tested for detection of volatile organic compounds (benzene, formaldehyde and naphthalene) at ppb level concentrations, with various ethanol backgrounds (0.5 and 2 ppm) and gas humidities (30, 50 and 70 % RH). The gas sensors were operated in temperature cycled operation. For signal processing, linear discriminant analysis was performed using features extracted from the conductance signals during temperature variations as input data.Both WO 3 sensor layers showed high sensitivity and selectivity to naphthalene compared to the other target gases. Of the two layers, the one prepared at higher oxygen partial pressure showed higher sensitivity and stability resulting in better discrimination of the gases and of different naphthalene concentrations. Naphthalene at concentrations down to 1 ppb could be detected with high reliability, even in an ethanol background of up to 2 ppm. The sensors show only low response to ethanol, which can be compensated reliably during the signal processing. Quantification of ppb level naphthalene concentrations was also possible with a high success rate of more than 99 % as shown by leave-one-out cross validation.

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Section: Crystal Structure Characterization Of the Sensing Layersmentioning

confidence: 99%

Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition

Leidinger

Huotari

Sauerwald

et al. 2016

J. Sens. Sens. Syst.

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“…In addition to the synthesis methodology, it has been observed that the architecture of bimetallic NPs can be modified by thermal treatment in the presence of H 2 , O 2 or Ar. 107 In the following sections, the reported application of bimetallic NPs in the selective hydrogenation of alkynes will be described according to the type of substrate used in catalysis and the metal combinations.…”

Section: Dilution Of the Active Phase: Introduction Of Modifiersmentioning

confidence: 99%

Advances in the preparation of highly selective nanocatalysts for the semi-hydrogenation of alkynes using colloidal approaches

et al. 2017

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In the last decade, the semi-hydrogenation of alkynes has experienced significant advances in terms of fine control of alkene selectivity and prevention of the over-hydrogenation reaction. Such advances have been possible to a large extent through the progress in colloidal methods for the preparation of metallic nanoparticles. The present review describes the contributions in the field of the selective hydrogenation of alkynes involving the utilization of colloidal methodologies. These approaches permit the fine modulation of several parameters affecting the catalytic performance of the active phase such as the particle size, the bulk and the surface structure and composition. For the transformation of liquid substrates, the nature of the stabilizers, the reducing agents and the metal precursors employed for the synthesis of the catalysts can be tuned to enhance the alkene selectivity. In contrast, in catalytic transformations of gaseous substrates, the presence of adsorbed species at the metal surface usually gives detrimental results while the interplay between the support and the active phase appears to be a more convincing alternative for catalyst tuning.

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“…The initial slope of the curve giving A (l, sn) according to the length L columns is inversely proportional to the apparent size of the crystallites in a direction perpendicular to the plane (hkl) considered (Figure 1). This apparent size is given by the following equation [18,19]. From the Figure 1, the point of intersection of the initial slope of the curve with the x-axis (L) provides the size Df.…”

Section: Introductionmentioning

confidence: 99%

X-Ray Peak Profile Analysis of Materials M1 and M2 by Williamson-Hall and Size-Strain Plot Methods

Khier¹,

Abdelghani²,

Maouche³

2021

ACSM

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In this work, we have studied the Kaolin M1 and M2 by the X-ray diffraction method, and we have focused on mullite phase which is the main phase present in common in both products. An update of the program of the method of Stokes was carried out, it was necessary to the microstructural analysis. The completed version is less sensitive to the choice by excess of the number of coefficients of Fourier with regard to the effect of truncation and the office plurality of the errors. The determination of the symmetry of the cell of the principal phase (mullite) in the studied fritted Kaolins was carried out. In Kaolin M1, the size of crystallites of the dominant phase varies between 80 to 170 Å. In Kaolin M2, the size of the crystalline grains of mullite varies between 100 to 400 Å. The size of crystallites was confirmed by the joint method of Williamson-Hall. A distribution of sizes of crystallites was carried out. It shows a dominance of the size of approximately 140 Å for the principal phase of Kaolin M1 and a dominance of the size of approximately 230 Å for the same principal phase of Kaolin M2. By the study of the profiles of line by DRX, it appears very clearly that the principal phase of the various sintered Kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted not only at low temperature (1100℃) during 1 hour but also the case of the mixtures of the type ‘chamotte’ cooks with 1350℃ during very long times.

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A comparison between the Warren-Averbach method and alternate methods for X-ray diffraction microstructure analysis of polycrystalline specimens

Cited by 35 publications

References 26 publications

Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition

Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition

Advances in the preparation of highly selective nanocatalysts for the semi-hydrogenation of alkynes using colloidal approaches

X-Ray Peak Profile Analysis of Materials M1 and M2 by Williamson-Hall and Size-Strain Plot Methods

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A comparison between the Warren-Averbach method and alternate methods for X-ray diffraction microstructure analysis of polycrystalline specimens

Cited by 35 publications

References 26 publications

Selective detection of naphthalene with nanostructured WO&lt;sub&gt;3&lt;/sub&gt; gas sensors prepared by pulsed laser deposition

Selective detection of naphthalene with nanostructured WO&lt;sub&gt;3&lt;/sub&gt; gas sensors prepared by pulsed laser deposition

Advances in the preparation of highly selective nanocatalysts for the semi-hydrogenation of alkynes using colloidal approaches

X-Ray Peak Profile Analysis of Materials M1 and M2 by Williamson-Hall and Size-Strain Plot Methods

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Product

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Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition

Selective detection of naphthalene with nanostructured WO<sub>3</sub> gas sensors prepared by pulsed laser deposition