scholarly journals Electric-Loading Enhanced Kinetics in Oxide Ceramics: Pore Migration, Sintering and Grain Growth: Final Report

2018 ◽  
Author(s):  
I-Wei Chen
Keyword(s):  
Grain Growth ◽  
Final Report ◽  
Oxide Ceramics ◽  
Electric Loading

Microwave-Material Interaction in Oxide Ceramics with Different Additives

2006 ◽  
Vol 45 ◽  
pp. 845-850
Author(s):  
Monika Willert-Porada ◽  
Zahra Negahdari ◽  
T. Gerdes ◽  
Achim Müller ◽  
M. Paneerselvam
Keyword(s):  
Grain Growth ◽  
Microwave Field ◽  
Volume Ratio ◽  
Conventional Heating ◽  
Small Samples ◽  
Oxide Ceramics ◽  
Volumetric Heating ◽  
Conventional Sintering ◽  
Grain Boundary Pinning ◽  
Material Interaction

A systematic study upon microwave (2.45 GHz frequency) and conventional heating (resistance heating furnace) was undertaken on porosity, grain growth and densification of commercial grade Al2O3-ceramics doped with MgO (aliovalent doping), with ZrO2 (grain boundary pinning) and with additives promoting elongated grain growth (LaAlO 3 and La2O3, AlPO4). Processes accompanied by a strong non-equilibrium situation, e.g., dissolution, segregation, vacancy formation, are influenced by the presence of the microwave field during heat treatment, visible on microstructure differences of microwave as compared to conventionally sintered samples. Regular grain growth is almost not affected by the microwave field, but the on-set of exaggerated grain growth and pore coalescence is delayed and occurs at higher density as compared to conventional sintering. Such microstructure differences seem to be more pronounced if the surface to volume ratio of the samples is low, therefore volumetric heating has a larger contribution to transport phenomena as compared to small samples.

Grain growth control in nanocrystalline oxide ceramics

1995 ◽  
Vol 6 (5-8) ◽  
pp. 851-854 ◽  
Author(s):  
A. Kats-Demyanets ◽  
R. Chaim
Keyword(s):  
Grain Growth ◽  
Growth Control ◽  
Oxide Ceramics ◽  
Nanocrystalline Oxide

Densification and High Temperature Deformation in Oxide Ceramics

2008 ◽  
Vol 395 ◽  
pp. 39-54 ◽  
Author(s):  
Atul H. Chokshi
Keyword(s):  
High Temperature ◽  
Grain Growth ◽  
Diffusion Processes ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Oxide Ceramics ◽  
Deformation And Failure ◽  
Kinetics Of

Bulk ceramics are usually obtained from sintering of powders, involving both densification and growth. The kinetics of grain growth are examined with a view to producing bulk nanoceramics. The high temperature deformation and failure of oxide ceramics are also examined with reference to diffusion processes.

Microstructure and mechanical properties of NiAl/Al2O3 composites

1999 ◽  
Vol 14 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Chii-Shyang Hwang ◽  
Tien-Jui Liu
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Oxide Scale ◽  
Grain Growth ◽  
Hot Pressing ◽  
Oxide Ceramics ◽  
Matrix Composites ◽  
Vacuum Atmosphere ◽  
Nial Powder ◽  
Nial Matrix

To improve mechanical properties of NiAl, a method for making NiAl matrix composites containing oxide ceramics is introduced. The method involves oxidation of NiAl powder in air to form a thin and uniform oxide scale, mainly Al2O3, on the NiAl particles. The Al2O3 contents increase with increasing oxidation temperature. The NiAl/Al2O3 composites are then formed by hot-pressing the oxidized NiAl powder under vacuum atmosphere. Al2O3 inhibits the grain growth of NiAl during the hot-pressing. The residual stress and the Ni-rich NiAl composition exist in the hot-pressed NiAl/Al2O3 composites. Strength and toughness data on NiAl/Al2O3 composites indicate that the use of oxidation of NiAl powder is a viable technique for improving these properties over that of monolithic NiAl.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

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