Liquid-Film Assisted Mechanism of Reactive Flash Sintering in Oxide Systems

Rachman Chaim; Yaron Amouyal

doi:10.3390/ma12091494

Liquid-Film Assisted Mechanism of Reactive Flash Sintering in Oxide Systems

Materials ◽

10.3390/ma12091494 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1494 ◽

Cited By ~ 4

Author(s):

Rachman Chaim ◽

Yaron Amouyal

Keyword(s):

Liquid Film ◽

Binary Systems ◽

Solid Phase ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Onset Temperature ◽

Phase Assemblage ◽

Reaction Products ◽

Oxide Systems ◽

Flash Sintering

Reactive flash sintering in oxide systems is analyzed assuming the formation of a liquid film at the particle contacts at the flash onset temperature. Formation of intermediate phases, as well as phase assemblage, are predicted upon optimal conditions of the electric field and current density. In single-phase impure oxides, the solidus and the solubility limit determine the flash onset temperature. In reacting binary systems, the composition of the liquidus determines primarily the reaction products during the cooling. In multicomponent systems, the oxide with the lowest flash temperature forms the interfacial liquid film, and the solid phase assemblage follows the equilibrium phase diagram. Examples from literature are consistent with reactive flash sintering and flash sintering assisted by a transient liquid film.

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Correlation of Melting Results for Both Pure Substances and Impure Substances

Journal of Heat Transfer ◽

10.1115/1.3246985 ◽

1986 ◽

Vol 108 (3) ◽

pp. 649-653 ◽

Cited By ~ 15

Author(s):

E. M. Sparrow ◽

G. A. Gurtcheff ◽

T. A. Myrum

Keyword(s):

Solid Phase ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Vertical Tube ◽

Step Change ◽

Pure Substance ◽

Characteristic Temperatures ◽

Pure Substances ◽

T Values ◽

Melting Experiments

Melting experiments were performed encompassing both pure and impure substances. The pure substances included n-octadecane paraffin and n-eicosane paraffin, while the impure substances were mixtures synthesized from the pure paraffins. The experiments were carried out in a closed vertical tube whose wall was subjected to a step-change increase in temperature to initiate the melting. For each impure substance, supplementary measurements were made of two characteristic temperatures: the temperature T** at which melting of the solid phase first begins and the lowest temperature T* at which the melting can go to completion. For a pure substance, T** = T*. The time-dependent melting results for all the investigated substances, both pure and impure, were well correlated as a function of FoSte**(Gr**)1/8 alone, where the ** signifies the presence of T** in the temperature difference which appears in Ste and Gr. This correlation enables melting rates for impure substances to be determined from melting rates for pure substances. The T** values needed for the implementation of the correlation can be obtained from simple experiments, obviating the need for the complete equilibrium phase diagram.

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Studies on the Reaction between Thiocarbamylsulfenamides and Diebenzothiazyl Disulfide

Rubber Chemistry and Technology ◽

10.5254/1.3538128 ◽

1983 ◽

Vol 56 (2) ◽

pp. 327-336 ◽

Cited By ~ 6

Author(s):

Basudam Adhikari ◽

Dhananjay Pal ◽

Dipak Kumar Basu ◽

Ajit Kumar Chaudhuri

Keyword(s):

Free Radicals ◽

Binary Systems ◽

Solid Phase ◽

Synergistic Activity ◽

Reaction Products ◽

Vulcanization Process ◽

Insight Into ◽

Accelerator System

Abstract The use of binary systems as accelerators in the vulcanization of rubber has received considerable attention, since many of them in suitable combinations, have been shown to provide efficient vulcanization systems. Dogadkin and co-workers and Skinner and Watson reported mutual activation with a number of popular accelerator combinations. It was suggested that the mutual activation occurs by the interaction of the accelerators to form intermediate complexes which decompose to produce free radicals responsible for initiating the various reactions involved in the vulcanization process. Recently Krymowski and Taylor studied the reaction between N-oxydiethylenethiocarbamyl-N′-oxydiethylenesulfenamide (OTOS) and N-oxydiethylene-2-benzothiazylsulfenamide (OBTS), a synergistic accelerator system, in tetrachloroethane at 142°C, and identified the various products formed. Many of these reaction products themselves are familiar as vulcanization accelerators and thus may contribute to the synergistic activity observed with the OTOS-OBTS system. In the present investigation, we have studied the reaction between thiocarbamylsulfenamides and dibenzothiazyl disulfide (MBTS) in the solid phase in order to get an insight into the mutual activity provided by this system in filled and gum vulcanizates of NR.

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Phase-Field Modelling of radiation induced microstructures

MRS Proceedings ◽

10.1557/opl.2015.360 ◽

2015 ◽

Vol 1743 ◽

Author(s):

L. Luneville ◽

G. Demange ◽

V. Pontikis ◽

D. Simeone

Keyword(s):

Phase Diagram ◽

Phase Field ◽

Binary Systems ◽

Canonical Ensemble ◽

Excess Free Energy ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Miscibility Gap ◽

Radiation Induced ◽

Grand Canonical

ABSTRACTThis work shows that realistic irradiation-induced phase separation and the resulting microstructures can be obtained via an adapted Phase Field (PF) modelling combined with atomistic Monte Carlo simulations in the pseudo-grand canonical ensemble. The last allow for calculating the equilibrium phase diagram of the silver-copper alloy, chosen as a model of binary systems with large miscibility gap and, for extracting the parameters of the excess free-energy PF functional. Relying on this methodology, the equilibrium phase diagram of the alloy is predicted in excellent agreement with its experimental counterpart whereas, under irradiation, the predicted microstructures are functions of the irradiation parameters. Different irradiation conditions trigger the formation of various microstructures consistently presented as a non-equilibrium “phase diagram” aiming at facilitating the comparison with experimental observations.

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Prediction of phase equilibria in the In-Sb-Pb system

Journal of the Serbian Chemical Society ◽

10.2298/jsc0803377m ◽

2008 ◽

Vol 73 (3) ◽

pp. 377-384

Author(s):

Dusko Minic ◽

Dragan Manasijevic ◽

Dragana Zivkovic ◽

Nada Strbac ◽

Zvonimir Stankovic

Keyword(s):

Experimental Data ◽

Phase Diagram ◽

Phase Equilibria ◽

Binary Systems ◽

Equilibrium Phase ◽

Calculated Phase Diagram ◽

Equilibrium Phase Diagram ◽

Thermodynamic Prediction ◽

Calculated Liquidus ◽

Good Agreement

Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In-Sb, Pb-Sb and In-Pb, were used for the prediction of the phase equilibria in the ternary In-Sb-Pb system. The predicted equilibrium phase diagram of the vertical Pb-InSb section was compared with the results of differential thermal analysis (DTA) and optical microscopy. The calculated phase diagram of the isothermal section at 300 ?C was compared with the experimentally (SEM, EDX) determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynamic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In-Sb-Pb system is also presented.

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Stability, Instability, Metastability and Grain Size in Nanocrystalline Ceramic Oxide Systems

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.140.29 ◽

2008 ◽

Vol 140 ◽

pp. 29-36 ◽

Cited By ~ 10

Author(s):

Giora Kimmel ◽

Jacob Zabicky

Keyword(s):

Grain Size ◽

Low Temperature ◽

Solid Solutions ◽

Equilibrium Phase ◽

Phase Evolution ◽

Equilibrium Phase Diagram ◽

Tetragonal Zro2 ◽

Oxide Systems ◽

Oxide Phases ◽

Higher Temperature

The following nanocrystalline binary oxide systems were studied: Mg-Ti, Ni-Ti, Zr-Al, as well as some pure and doped unary oxides. The xerogels were heated at a constant T (200 to 1600°C) for 3 to 6 hours. There was a threshold tempearture for oxide formation and in many cases the products were metastable nanocrystalline phases, depending on the grain size and composition, including doping. The oxide phases of Ni-Ti, Mg-Ti, and Zr-Al, formed at 900 °C are different from those formed at higher temperature. New ranges of solid solutions and the formations of higher temperature structures were found. A transition phase can be defined as a structure formed at relative low tempearture, irreversibly transforming at higher temperature into an equilibrium phase of the same elemental composition. Some low temperature transition phases have a structure similar to that of a high temperature equilibrium phase, e.g., (the equilibrium phase is given in parentheses) tetragonal ZrO2 (monoclinic) and low-T qandilite-like solid solutions (qandilite + geikielite). Others are unique with no representation in the equilibrium phase diagram, e.g., gamma-like alumina (corundum) and anatase (rutile), which are formed as nanocrystalline oxides due to a low growth rate caused either by a low temperature of calcination or due to additives. To asses the importance of crystal size in the stabilization of transition phases, the following studies were undertaken: (a) XRPD analysis of all unary, doped and binary compositions; (b) the evolution of transition phases in HT XRPD of the Mg titanates; (c) the phase evolution was studied with time at temperatures were mixtures of transition and equilibrium phases were found; (d) the retention of pure tetragonal ZrO2 on quenching Al-Zr oxides after calcinations at high tempetature; (e) additional evidence from HRTEM, SEM and DTA experiments was also collected. A model, correlating the size effect with the unusual phases and structures is proposed.

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Effect of the Hybrid Hydrophobic-Hydrophilic Nanostructured Surface on Explosive Boiling

Coatings ◽

10.3390/coatings11020212 ◽

2021 ◽

Vol 11 (2) ◽

pp. 212

Author(s):

Ming-Jun Liao ◽

Li-Qiang Duan

Keyword(s):

Liquid Film ◽

Coating Thickness ◽

Bubble Nucleation ◽

Onset Temperature ◽

Dynamics Simulation ◽

Hydrophilic Surface ◽

Pillar Width ◽

Nanostructured Surface ◽

Explosive Boiling ◽

Hydrophobic Coating

The influence of different wettability on explosive boiling exhibits a significant distinction, where the hydrophobic surface is beneficial for bubble nucleation and the hydrophilic surface enhances the critical heat flux. Therefore, to receive a more suitable surface for the explosive boiling, in this paper a hybrid hydrophobic–hydrophilic nanostructured surface was built by the method of molecular dynamics simulation. The onset temperatures of explosive boiling with various coating thickness, pillar width, and film thicknesses were investigated. The simulation results show that the hybrid nanostructure can decrease the onset temperature compared to the pure hydrophilic surface. It is attributed to the effect of hydrophobic coating, which promotes the formation of bubbles and causes a quicker liquid film break. Furthermore, with the increase of the hydrophobic coating thickness, the onset temperature of explosive boiling decreases. This is because the process of heat transfer between the liquid film and the hybrid nanostructured surface is inevitably enhanced. In addition, the onset temperature of explosive boiling on the hybrid wetting surface decreases with the increase of pillar width and liquid film thickness.

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Phase Formation, Microstructure and Mechanical Properties of Mg67Ag33 as Potential Biomaterial

Metals ◽

10.3390/met11030461 ◽

2021 ◽

Vol 11 (3) ◽

pp. 461

Author(s):

Konrad Kosiba ◽

Konda Gokuldoss Prashanth ◽

Sergio Scudino

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Equilibrium Phase ◽

Antibacterial Properties ◽

Equilibrium Phase Diagram ◽

Compressive Yield Strength ◽

X Ray ◽

Fine Grained ◽

Equilibrium Phases

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.

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Intermetallic Formation in the Aluminum–Copper System

Surface Review and Letters ◽

10.1142/s0218625x03005396 ◽

2003 ◽

Vol 10 (04) ◽

pp. 677-683 ◽

Cited By ~ 20

Author(s):

E. B. Hannech ◽

N. Lamoudi ◽

N. Benslim ◽

B. Makhloufi

Keyword(s):

Electron Microscopy ◽

Phase Diagram ◽

Solid Solution ◽

Intermetallic Layer ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Diffusion Couples ◽

Intermetallic Formation ◽

Parabolic Law ◽

Scanning Electron

Intermetallic formation at 425°C in the aluminum–copper system has been studied by scanning electron microscopy using welded diffusion couples. Several Al–Cu phases predicted by the equilibrium phase diagram of the elements and voids taking place in the diffusion zone have been detected in the couples. The predominant phases were found to be Al 2 Cu 3 and the solid solution of Al in Cu, α. The growth of the intermetallic layer obeyed the parabolic law.

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