Grain boundary diffusion driven spark plasma sintering of nanocrystalline zirconia

2012 ◽  
Vol 38 (5) ◽  
pp. 4385-4389 ◽  
Author(s):  
Hanna Borodianska ◽  
Dmytro Demirskyi ◽  
Yoshio Sakka ◽  
Petre Badica ◽  
Oleg Vasylkiv
Keyword(s):  
Grain Boundary ◽  
Spark Plasma Sintering ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Nanocrystalline Zirconia

scholarly journals Thermo-electro-mechanical modeling of spark plasma sintering processes accounting for grain boundary diffusion and surface diffusion

2021 ◽  
Vol 67 (5) ◽  
pp. 1395-1407
Author(s):  
A. S. Semenov ◽  
J. Trapp ◽  
M. Nöthe ◽  
O. Eberhardt ◽  
B. Kieback ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Surface Diffusion ◽  
Spark Plasma Sintering ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Experimental Results ◽  
Interparticle Contact ◽  
Mechanical Problem ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractIn the present research, a numerical modeling approach of the initial stage of consolidation during spark plasma sintering on the microscopic scale is presented. The solution of a fully coupled thermo-electro-mechanical problem also accounting for grain boundary and surface diffusion is found by using a staggered way. The finite-element method is applied for solving the thermo-electro-mechanical problem while the finite-difference method is applied for the diffusion problem. A Lagrange-based non-linear formulation is used to deal with the detailed description of plastic and creep strain accumulation. The numerical model is developed for simulating the structural evolution of the involved particles during sintering of powder compacts taking into account both the free surface diffusion of the particles and the grain boundary diffusion at interparticle contact areas. The numerical results obtained by using the two-particle model—as a representative volume element of the powder—are compared with experimental results for the densification of a copper powder compact. The numerical and experimental results are in excellent agreement.

Grain-boundary diffusion coefficient in α-Al2O3 from spark plasma sintering tests: Evidence of collective motion of charge disconnections

2018 ◽  
Vol 44 (15) ◽  
pp. 19044-19048 ◽  
Author(s):  
Yoshihiro Tamura ◽  
Eugenio Zapata-Solvas ◽  
Bibi Malmal Moshtaghioun ◽  
Diego Gómez-García ◽  
Arturo Domínguez-Rodríguez
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Spark Plasma Sintering ◽  
Boundary Diffusion ◽  
Collective Motion ◽  
Grain Boundary Diffusion ◽  
Plasma Sintering ◽  
Boundary Diffusion Coefficient ◽  
Spark Plasma ◽  
Α Al2o3

Densification mechanism involved during spark plasma sintering of a codoped α-alumina material: Part I. Formal sintering analysis

2009 ◽  
Vol 24 (1) ◽  
pp. 179-186 ◽  
Author(s):  
G. Bernard-Granger ◽  
C. Guizard
Keyword(s):  
Grain Boundary ◽  
Spark Plasma Sintering ◽  
Boundary Diffusion ◽  
Grain Boundary Sliding ◽  
Alumina Powder ◽  
Densification Mechanism ◽  
Material Part ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Boundary Sliding

Spark plasma sintering (SPS) of a codoped α-alumina powder has been investigated at temperatures between 850 and 1200 °C. The “grain size versus relative density” trajectory showed a significant grain growth as soon as the residual porosity closed. The densification mechanism was determined by anisothermal (investigation of the heating part of a SPS run) and isothermal methods. It was proposed that grain-boundary sliding, accommodated by oxygen grain-boundary diffusion, governed densification.

The Grain Boundary Diffusion Kinetics in Nanocrystalline Zirconia

1996 ◽  
Vol 458 ◽  
Author(s):  
A. P. Zhilyaev ◽  
V. Y. Gertsman ◽  
J. A. Szpunar
Keyword(s):  
Grain Boundary ◽  
Oxidation Rate ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Different Types ◽  
Nanocrystalline Zirconia ◽  
Boundary Character Distribution

ABSTRACTIt is expected that the grain boundary diffusion is the principal contributor to the transport properties of nanocrystalline zirconia, and that it controls the oxidation kinetics and hydrogen permeation. This process depends on the grain boundary character distribution (i.e. the fractions of different grain boundary types) and on the topological characteristics of the grain boundary network. Modeling of the random walk problem on a planar honeycomb network for different types of the grain boundary misorientation distributions (GBMD) in nanocrystalline zirconia film is presented in the current paper. The GBMD was calculated using the model texture. Changes of the oxidation rate for different types of the grain boundary character distribution and different ratios of the bulk and grain boundary diffusion coefficients are analyzed. In this study it was found that an increase of the frequency of low energy boundaries lowers the oxidation rate.

High Hardness BaCb-(BxOy/BN) Composites with 3D Mesh-Like Fine Grain-Boundary Structure by Reactive Spark Plasma Sintering

2012 ◽  
Vol 12 (2) ◽  
pp. 959-965 ◽  
Author(s):  
Oleg Vasylkiv ◽  
Hanna Borodianska ◽  
Petre Badica ◽  
Salvatore Grasso ◽  
Yoshio Sakka ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Spark Plasma Sintering ◽  
High Hardness ◽  
Boundary Structure ◽  
3D Mesh ◽  
Fine Grain ◽  
Grain Boundary Structure ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Flash Spark Plasma Sintering of 3YSZ: Modified Sintering Pathway and Impact on Grain Boundary Formation

2021 ◽  
Author(s):  
Thomas Hérisson de Beauvoir ◽  
Zakaria Ghomari ◽  
Geoffroy Chevallier ◽  
Andréas Flaureau ◽  
Alicia Weibel ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Spark Plasma Sintering ◽  
Boundary Formation ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Limitations in the Grain Boundary Processing of the Recycled HDDR Nd-Fe-B System

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3528
Author(s):  
Awais Ikram ◽  
Muhammad Awais ◽  
Richard Sheridan ◽  
Allan Walton ◽  
Spomenka Kobe ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Diffusion Mechanism ◽  
Mass Gain ◽  
Grain Boundary Diffusion ◽  
Eutectic Alloys ◽  
Intergranular Phase ◽  
Spark Plasma ◽  
Diffusion Source ◽  
Secondary Annealing

Fully dense spark plasma sintered recycled and fresh HDDR Nd-Fe-B nanocrystalline bulk magnets were processed by surface grain boundary diffusion (GBD) treatment to further augment the coercivity and investigate the underlying diffusion mechanism. The fully dense SPS processed HDDR based magnets were placed in a crucible with varying the eutectic alloys Pr68Cu32 and Dy70Cu30 at 2–20 wt. % as direct diffusion source above the ternary transition temperature for GBD processing followed by secondary annealing. The changes in mass gain was analyzed and weighted against the magnetic properties. For the recycled magnet, the coercivity (HCi) values obtained after optimal GBDP yielded ~60% higher than the starting recycled HDDR powder and 17.5% higher than the SPS-ed processed magnets. The fresh MF-15P HDDR Nd-Fe-B based magnets gained 25–36% higher coercivities with Pr-Cu GBDP. The FEG-SEM investigation provided insight on the diffusion depth and EDXS analysis indicated the changes in matrix and intergranular phase composition within the diffusion zone. The mechanism of surface to grain boundary diffusion and the limitations to thorough grain boundary diffusion in the HDDR Nd-Fe-B based bulk magnets were detailed in this study.

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