Effect of initial particle size distribution on the dynamics of transient Ostwald ripening: A phase field study

Li, Junjie; Guo, Chunwen; Ma, Yiwei; Wang, Zhijun; Wang, Jincheng

doi:10.1016/j.actamat.2015.02.030

Cited by 44 publications

(45 citation statements)

References 61 publications

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“…Therefore, the fact that in Y123 samples with addition of seed grains the width of the grain size distribution of FGM is wider than that of the reference samples and the mean grain size grows faster indicates that the large grains grown on the seed grains influence the grain size distribution of FGM and, accordingly, the growth rate of FGM. This assumption is supported by modeling data showing that the microstructure that has an initially long tail of distribution corresponding to large grains is most rapidly coarsened [20]. Another factor is possible that promotes the acceleration of the growth of FGM in samples with addition of a seed grains.…”

Section: Discussionsupporting

confidence: 58%

Microstructure of superconducting ceramics YBa2Cu3O7–x sintered with addition of seed grains

Imayev¹,

Kabirova²,

Yakshibayeva³

2017

LoM

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The growth of seed grains of YBa 2 Cu 3 O 7-x (Y123) ceramics in fine-grained matrix was studied. For this, two batches of powders were prepared. The first batch consisted only of fine-grained powder with a particle size less than 1 μm and was used to prepare the so-called reference samples. The second batch was a fine-grained powder with addition of 5 wt. % seed grains with sizes 60 -80 μm. Powders were pressed and sintered in the temperature range 925 -1000°C for 5 h. The effect of sintering temperature on density, grain size, structure of the seed-growth zone were investigated. In samples of both types the highest density is observed after sintering at T = 925 °C, and at higher temperatures the density decreases due to a release of oxygen as a result of a partial decomposition of the Y123 phase on grain boundaries. Above T ≈ 960°C the density of the reference samples decreases more strongly than in the samples with seeds. Seeds initiate the growth of anomalously large grains. The strongest growth of large grains occurs at T ≈ 960°C. Above T ≈ 960°C the grain growth is significantly slowed down that is associated with an increase in porosity of the samples. Large grains affect the growth of grains of fine-grained matrix: in the samples with seeds the mean grain size of fine-grained matrix is higher than in the reference samples. A scheme explaining the effect of seed grains on grain growth of fine-grained matrix is proposed.

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Section: Discussionsupporting

confidence: 58%

Microstructure of superconducting ceramics YBa2Cu3O7–x sintered with addition of seed grains

Imayev¹,

Kabirova²,

Yakshibayeva³

2017

LoM

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“…Lifshitz and Slyozov [44] and Wagner [45] (LSW) derived the first analytical description of particle coarsening in binary alloy systems, in which the predicted coarsening rate of the mean particle size is reported to be proportional to time 1/3 . In recent decades, the theory proposed by LSW has been extended to multicomponent alloys such as Ni superalloys [46][47][48][49][50][51][52], Ti alloys [53][54][55] and other types of alloys [56][57][58]. However, application of LSW theory to MCrAlY alloys does not appear to have been previously reported.…”

Section: Introductionmentioning

confidence: 95%

An analytical approach to the β-phase coarsening behaviour in a thermally sprayed CoNiCrAlY bond coat alloy

Chen

McCartney

2017

Journal of Alloys and Compounds

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This paper investigates the β-phase coarsening behaviour during isothermal heat treatment of free-standing CoNiCrAlY (Co-31.7%Ni-20.8%Cr-8.1%Al-0.5%Y, all in wt%) coatings prepared by high velocity oxy-fuel (HVOF) thermal spraying. The microstructure of the coatings was characterised using scanning electron microscopy with energy dispersive X-ray (EDX) analysis and electron backscatter diffraction (EBSD). It comprises a two phase structure of fcc γ-Ni matrix and bcc β-NiAl precipitates. The volume fraction of the γ-Ni and the β-NiAl phases were measured to be around 70% and 30% respectively, with grain sizes varying largely from 0.5 to 2 µm for both phases. Isothermal heat treatments of the freestanding coatings were carried out at 1100 C for times up to 250 h. The β-phase coarsening behaviour during isothermal heat treatments was analysed by quantitative metallography. It is shown that the coarsening behaviour of β phase in the CoNiCrAlY alloy followed the classical Lifshitz-Slyozov-Wagner (LSW) theory of Ostwald ripening. By incorporating a dimensionless factor which correlates with volume fraction of the β phase, a modified LSW model coupled with formulaic interfacial energy and effective diffusion coefficient of the 2 CoNiCrAlY alloy was utilised to interpret the coarsening behaviour of the β phase. The coarsening rate coefficient obtained from the modified LSW model shows good agreement with the corresponding experimental result.

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“…Nanoemulsions are colloidal dispersions similar to conventional emulsions. Compared with conventional emulsions, nanoemulsions have the small droplet size and the highly kinetic stability, which guarantee the use as delivery systems [6,7]. As known, nanoemulsions are thermodynamically unstable systems that tend to break down due to a variety of physicochemical mechanisms, such as Ostwald ripening, flocculation, coalescence, and creaming [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Oil Type, Aliphatic Alcohol, and Ionic Surfactants on the Formation and Stability of Ceramide-2 Enriched Nanoemulsions

Tian

Guo²,

Zhang

2015

Journal of Dispersion Science and Technology

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Oil-in-water nanoemulsions are finding increasing use as delivery systems to encapsulate lipophilic bioactive components in personal care and pharmaceutical. The aim of this study was to optimize the composition and stability of ceramide-2 nanoemulsions. The nanoemulsions were prepared by high pressure homogenizer emulsification method using sodium dilauramidoglutamide lysine (DLGL) as surfactant. Results showed that the oil type and concentration had an appreciable impact on the particle size and stability of the ceramide-2 enriched nanoemulsions. The presence of the aliphatic alcohol altered the curvature of the surfactant molecular and increased the stability of nanoemulsions. The zeta potential of nanoemulsions decreased with the addition of Cetyl trimethyl ammonium Chloride (1631), which weakens the electrostatic interactions between droplets and lowers the stability of the nanoemulsions. The particle size decreased with increasing concentrations of both sodium dodecyl sulfate (SDS) and Cocoamidopropyl Betaine (CAB). The variation of zeta potential with SDS and CAB was insignificant, which was attributed to the high zeta potential value resulted from anionic gemini surfactant DLGL. Downloaded by [University of Nebraska, Lincoln] at 22:58 26 August 2015 2The instability mechanism of nanoemulsions was the Ostwald ripening. This study demonstrated that the addition of aliphatic alcohol, SDS or CAB was beneficial to the stability of ceramide-2 nanoemulsions and decreased the Ostwald ripening rate.

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Effect of initial particle size distribution on the dynamics of transient Ostwald ripening: A phase field study

Cited by 44 publications

References 61 publications

Microstructure of superconducting ceramics YBa2Cu3O7–x sintered with addition of seed grains

Microstructure of superconducting ceramics YBa2Cu3O7–x sintered with addition of seed grains

An analytical approach to the β-phase coarsening behaviour in a thermally sprayed CoNiCrAlY bond coat alloy

Effect of Oil Type, Aliphatic Alcohol, and Ionic Surfactants on the Formation and Stability of Ceramide-2 Enriched Nanoemulsions

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