scholarly journals Measurements about the effect of grain boundaries on the electrical resistivity of uranium dioxide

1972 ◽  
Vol 45 (2) ◽  
pp. 171-173 ◽  
Author(s):  
W. Schikarski ◽  
G. Ondracek
Keyword(s):  
Electrical Resistivity ◽  
Grain Boundaries ◽  
Uranium Dioxide

Helium release in uranium dioxide in relation to grain boundaries and free surfaces

2010 ◽  
Vol 268 (11-12) ◽  
pp. 2133-2137 ◽  
Author(s):  
G. Martin ◽  
P. Garcia ◽  
C. Sabathier ◽  
G. Carlot ◽  
T. Sauvage ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Uranium Dioxide ◽  
Free Surfaces

Electrical Properties of Sb-Doped BaPbO3 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 653-655
Author(s):  
Xin Wang ◽  
Yu Dong Lu ◽  
Zhi Qiang Zhuang
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Curie Temperature ◽  
Grain Boundaries ◽  
Solid Solubility ◽  
Defect Structure ◽  
Sol Gel ◽  
Charge Carriers ◽  
Donor Concentration ◽  
Main Factor

Sb-doped BaPbO3 ceramics were prepared by sol-gel method. The influence of Pb/Ba ratio and Sb concentration on the electrical properties of BaPb1+x-ySbyO3 (x=0.0, 0.1, 0.2 and 0≤y≤0.2) compositions were investigated. Holes and Pb vacancies were the major defects in lightly donor-doped BaPbO3, where the increase of donor concentration resulted in decrease of charge carriers (holes), leading to resistivity increasing. In the highly donor-doped conditions, the microstructure or solid solubility substituted defect structure as the main factor affecting the variety of resistivity. The lowest electrical resistivity of Sb-doped BaPbO3 was 2.69 × 10-4 /·cm when the Sb concentration y=0.12~0.13. Excess of Pb causes the born of barium vacancies. And, the observed PTCR behavior of BaPb1.2O3 involves the Barium vacancies in grain boundaries. 0.5 mol% Sb-doped BaPbO3 showed the best PTCR behavior and its Curie temperature was about 850°C.

Effects of heat treatment and sintering additives on thermal conductivity and electrical resistivity in fine-grained SiC ceramics

2002 ◽  
Vol 17 (9) ◽  
pp. 2327-2333 ◽  
Author(s):  
Guo-Dong Zhan ◽  
Mamoru Mitomo ◽  
Amiya K. Mukherjee
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Electrical Resistivity ◽  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Laser Flash ◽  
Sintering Additives ◽  
Fine Grained ◽  
Resolution Electron ◽  
Thermal And Electrical Properties

The effects of heat treatment and sintering additives on the thermal conductivity and electrical resistivity of fine-grained SiC materials were investigated. The thermal conductivity and the electrical resistivity of dense SiC materials were measured at room temperature by a laser flash technique and a current-voltage method, respectively. The results indicated that the thermal conductivity and electrical resistivity of the SiC materials were dependent on the sintering additives and the resultant microstructure. Annealed materials with oxide additives developed microstructures consisting of elongated grains of various α/β–SiC polytypes. In contrast, annealed materials with oxynitride additives had microstructures consisting of fine equiaxed grains entirely of β–SiC phase. For the annealed materials with oxide additives the observed thermal conductivity was over 110 W/mK. For the annealed materials with oxynitride additives the observed value was 47 W/mK. The electrical resistivity of a hot-pressed material with oxide sintering additives decreased after annealing. For annealed materials with oxynitride additives, the electrical resistivity was even lower. High-resolution electron microscopy revealed a thin amorphous phase along the grain boundaries. Energy dispersive x-ray spectroscopy results showed that there was segregation of both Al and O atoms and a very small amount of Y atoms at grain boundaries. The results indicated that the chemistry and structure of the grain boundary has significant influence on thermal and electrical properties in SiC.

Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

2006 ◽  
Vol 985 ◽  
Author(s):  
Guillaume Martin ◽  
Pierre Desgardin ◽  
Philippe Garcia ◽  
Thierry Sauvage ◽  
Gaëlle Carlot ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Nuclear Reaction ◽  
Uranium Dioxide ◽  
Nuclear Reaction Analysis ◽  
Annealing Stage ◽  
Depth Profiles ◽  
Release Mechanisms ◽  
Helium Diffusion

AbstractThis study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO2 sintered samples presenting different microstructures were implanted with 3He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the 3He(d,α)1H reaction. 3He release is measured in-situ during sample annealing at temperatures ranging between 700°C and 1000°C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900°C in the vicinity of grain boundaries possibly as a result of the presence of defects.

Impact of Annealing on the Resistivity of Ultrafine Cu Damascene Interconnects

2003 ◽  
Vol 766 ◽  
Author(s):  
G. Steinlesberger ◽  
M. Engelhardt ◽  
G. Schindler ◽  
W. Steinhögl ◽  
M. Traving ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Resistivity ◽  
Size Effect ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Growth Process ◽  
Microstructural Change ◽  
Thermal Treatments ◽  
Annealing Conditions ◽  
Damascene Interconnects

AbstractThe influence of different annealing conditions on the electrical resistivity of copper damascene interconnects with lateral dimensions down to sub-50 nm was studied. Different thermal treatments after copper plating as well as annealing processes in addition to the final anneal step were carried out in order to study the microstructural change of copper damascene lines. It was found that rapid thermal annealing (RTA) at high temperatures (600°C) leads to an enlargement of the Cu grains by a factor of 2 for wide lines, whereas a significant impact of annealing on the median grain size of ultrafine lines was not observed. This is attributed to the geometrical limitation of the grain growth process. As a result, the size effect in Cu nano-interconnects which is mainly determined by grain boundaries acting as scattering sites for electrons cannot be reduced significantly by using thermal treatments.

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