Ostwald ripening during liquid phase sintering—Effect of volume fraction on coarsening kinetics

1984 ◽  
Vol 15 (6) ◽  
pp. 1081-1088 ◽  
Author(s):  
P. W. Voorhees ◽  
M. E. Glicksman
Keyword(s):  
Liquid Phase ◽  
Ostwald Ripening ◽  
Volume Fraction ◽  
Liquid Phase Sintering ◽  
Coarsening Kinetics ◽  
Sintering Effect

scholarly journals A mathematical approach to Ostwald ripening due to diffusion and deformation in liquid bridge

2013 ◽  
Vol 45 (3) ◽  
pp. 261-271 ◽  
Author(s):  
B. Randjelovic ◽  
K. Shinagawa ◽  
Z.S. Nikolic
Keyword(s):  
Liquid Phase ◽  
Liquid Bridge ◽  
Ostwald Ripening ◽  
Solid Phase ◽  
Liquid Phase Sintering ◽  
Solute Diffusion ◽  
Deformation Analysis ◽  
Mathematical Approach ◽  
Fe Method ◽  
Grain Coarsening

From many experiments with mixtures of small and large grains, it can be concluded that during liquid phase sintering, smaller grains partially dissolve and a solid phase precipitates on the larger grains and grain coarsening occurs. The growth rate can be controlled either by the solid-liquid phase boundary reaction or by diffusion through the liquid phase. The microstructure may change either by larger grains growing during the Ostwald ripening process or by shape accommodation. In this study, two-dimensional mathematical approach for simulation of grain coarsening by grain boundary migration based on a physical and corresponding numerical modeling of liquid phase sintering will be considered. A combined mathematical method of analyzing viscous deformation and solute diffusion in liquid bridge between two grains with different sizes will be proposed. The viscous FE method will be used for calculating meniscus of the liquid bridge, with the interfacial tensions taken into consideration. The FE method for diffusion will be also implemented by using the same mesh as the deformation analysis.

True Sedimentation and Particle Packing Rearrangement during Liquid Phase Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 609-612
Author(s):  
Jong K. Lee ◽  
Lei Xu ◽  
Shu Zu Lu
Keyword(s):  
Liquid Phase ◽  
Concentration Gradient ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Liquid Phase Sintering ◽  
Particle Packing ◽  
Sintering Process ◽  
Second Stage ◽  
Packing Efficiency ◽  
Two Stages

When an alloy such as Ni-W is liquid phase sintered, heavy solid W particles sedimentate to the bottom of the container, provided that their volume fraction is less than a critical value. The sintering process evolves typically in two stages, diffusion-driven macrosegregation sedimentation followed by true sedimentation. During sedimentation, the overall solid volume fraction decreases concurrently with elimination of liquid concentration gradient. However, in the second stage of true sedimentation, the average solid volume fraction in the mushy zone increases with time, and oddly, no concentration gradient is necessary in the liquid zone. In this work, we propose that the true sedimentation results from particle rearrangement for higher packing efficiency.

TiC plasma spray cermets

2020 ◽  
pp. 65-74
Author(s):  
V. I. Kalita ◽  
◽  
A. A. Radyuk ◽  
D. I. Komlev ◽  
A. B. Mikhailova ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Plasma Spray ◽  
Volume Fraction ◽  
Liquid Phase Sintering ◽  
Subsequent Formation ◽  
Initial Volume Fraction ◽  
The Matrix ◽  
High Microhardness ◽  
Reduction Of Oxides ◽  
Additional Hardening

The microstructure and microhardness of eleven volumetric cermets based on TiC carbide with nickel and cobalt based matrices after liquid-phase sintering at a temperature of 1400 °C were studied. It is supposed to use the research results for the subsequent formation of a powder for plasma spraying of coatings. The compositions of the matrix, additional hardening phases, and carbon were selected taking into account the specific features of the formation of plasma coatings: a decrease in the carbon content and high solidification rates of the sprayed particles with the formation of additional nanosized carbides and an increase in the volume fraction of carbides from 70 % to 88 %. As the matrix, we used the traditional composition for cermets with TiC carbide, NiCr – Mo,  and industrial powders, PGSR brands, Ni – 13.5 Cr – 2.7 Si – 4.5 Fe – 0.37 C – 1.65 B, and TAFA 1241F Co – 32 Ni – 21 Cr – 8  Al – 0.5 Y. The ring zone on TiC carbide is formed with the participation of WC, Cr3C2, TiN, matrix phases and additional carbon in the composition of cermets, 1 – 2.8 %, as a result, the initial volume fraction of TiC carbide increases 70 to 88 %. Additional carbon is consumed to reduce oxygen content at the stage of sintering (reduction of oxides). After sintering, cermets have high microhardness values at a load on an indenter of 20 G, 1940 – 3210 kgf/mm2, and lower values at a load on an indenter of 200  G, which was explained by a scale factor. The maximum calculated contribution of the hardness of the hardening phases to the hardness of the cermet was established for cermets with a Co matrix of 3681 kgf/mm2.

Three Dimensional Monte Carlo Simulation of Isotropic Coarsening of Particles in Liquid Phase

2007 ◽  
Vol 558-559 ◽  
pp. 1115-1120
Author(s):  
Suk Bin Lee ◽  
Anthony D. Rollett
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Liquid Phase ◽  
Ostwald Ripening ◽  
Monte Carlo Model ◽  
Liquid Phase Sintering ◽  
Three Dimensions ◽  
Average Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Coarsening of particles during liquid phase sintering is known to be an example of Ostwald ripening. This coarsening process, in a fully wetting system, is simulated in three dimensions with a kinetic Monte Carlo model. The results from the simulation for microstructures, kinetics and particle size distributions are compared to available experimental findings. It is found that the average particle volume increases linearly with time and that the particle size distributions are consistent with those obtained experimentally, as in the W-Ni-Fe and Sn-Pb systems.

3D Phase-Field Simulation and Characterization of Microstructure Evolution during Liquid Phase Sintering

2014 ◽  
Vol 87 ◽  
pp. 132-138 ◽  
Author(s):  
Hamed Ravash ◽  
Eckard Specht ◽  
Jef Vleugels ◽  
Nele Moelans
Keyword(s):  
Liquid Phase ◽  
Grain Boundary ◽  
Coordination Number ◽  
Dihedral Angle ◽  
Phase Field ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Liquid Phase Sintering ◽  
Study Phase ◽  
Solid Liquid

Liquid phase sintering (LPS) is widely used as a materials processing technique for hightemperature applications. In LPS, particle-particle contact size and distribution, 3-D coordination number, connectivity, and contiguity are important microstructure parameters which, to a large extent, determine the mechanical properties of the sintered materials. These features all depend on the grain size, solid volume fraction and dihedral angle during sintering. The dihedral angle is an important parameter in LPS. It is the angle formed between the 2 solid-liquid interfaces at the intersection of a grain boundary with the liquid. A higher solid volume fraction, on the other hand, favors a larger 3-D coordination number, connectivity, and contiguity. In practice, studying the correlation between these parameters and direct measurement of them is not a trivial task. Among them, 3-D measurement of dihedral angle is believed to be the most challenging one. In the current study, phase-field modeling is employed to simulate LPS in two phase systems (solid and liquid). Simulations are performed for the different ratios of grain boundary to solid-liquid energies and the different solid volume fractions. To create initial structures with high solid volume fraction, an advanced particle packing algorithm is employed. An extended sparse bounding-box algorithm is used to speed-up the computations and makes it computationally efficient for 3-D simulations. Contiguity, connectivity, and three dimensional coordination number were measured in the self similar regime. The results were compared with empirical rules and experimental data and are used to estimate the mean 3-D dihedral angle.

Liquid Phase Sintering of Barium Titanate Ceramics for High Energy Density Capacitors

2008 ◽  
Vol 368-372 ◽  
pp. 40-42 ◽  
Author(s):  
Jia Jia Huang ◽  
Yong Zhang
Keyword(s):  
Liquid Phase ◽  
Barium Titanate ◽  
Volume Fraction ◽  
Breakdown Strength ◽  
High Energy ◽  
Liquid Phase Sintering ◽  
High Energy Density ◽  
High Electrical Resistivity ◽  
Titanate Ceramics ◽  
Glass Compositions

Several glass compositions with high electrical resistivity were developed and added to the barium titanate ceramics. The glass additions were found to greatly increase the breakdown strength of the composite ceramics which has a 0-3 connectivity. The electrical properties of the liquid phase sintered ceramics are sensitive to the variations of the volume fraction and connectivity of the glass phase.

Effect of Interfacial Layers on the Performance of Cu-In Liquid Phase Sintered Composites as Thermal Interface and Interconnect Materials

2011 ◽  
Author(s):  
J. Liu ◽  
P. Kumar ◽  
I. Dutta ◽  
C. M. Nagaraj ◽  
R. Raj ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Yield Strength ◽  
Interfacial Layer ◽  
Volume Fraction ◽  
Liquid Phase Sintering ◽  
Thermal Interface ◽  
Interfacial Layers ◽  
Electrical Conductivities ◽  
Long Term Performance ◽  
Term Performance

In this study, a novel architecture composed of uniformly distributed high melting phase (HMP, e.g. Cu) in a low melting phase (LMP, e.g. In) matrix, which can be produced via liquid phase sintering (LPS), is proposed to produce next generation thermal interface materials (TIMs) and interconnect (IC) materials. The LMP determines the shear compliance of these composites whereas the HMP determines its thermal and electrical conductivities. The volume fraction of In was optimized to produce a Cu-In solder with suitable mechanical, electrical and thermal properties for TIM and IC applications. Since, Cu and In react to form several Cu-In intermetallic compounds (IMCs), which may deteriorate the long-term performance of these solders, interfacial-layers of Au and Al2O3 were applied on Cu to further improve the performance of the Cu-In solders. The effect of interfacial-layers on the reaction between Cu and In, during sintering at 160°C and during aging at 125°C, was studied and its impact on the mechanical, thermal and electrical properties was evaluated. Au interfacial layer (50∼200nm) quickly reacted with In to form AuIn2 IMC, which acted as a tenacious diffusion-barrier and slowed down the reactions between Cu and In. 8-monolayer thick Al2O3 did not react with either Cu or In and inhibited reactions between Cu and In. During short-time sintering, the effect of interfacial layer on the thicknesses of IMCs was insignificant to affect the yield strength of the as-sintered composites. However, IMC layer thickened rapidly in the Cu-In composites without an interfacial-layer, which led to a drastic decrease in the volume fraction of unreacted In leading to an increase in the yield strength of the solder. On the other hand, the interfacial-layers effectively suppressed the growth of IMCs during aging and hence the yield strength of such composites increased at slower rates. Since, the IMCs formed at the interface radically affect the contact resistance, significant differences in the thermal and electrical conductivities were recorded for the solders with different interfacial-layers.

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