scholarly journals BeO Utilization in Reactors for the Improvement of Extreme Reactor Environments - A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Li ◽  
Libo Qian ◽  
Xiaojing Li ◽  
Yu Ma ◽  
Wenzhong Zhou
Keyword(s):  
Thermal Conductivity ◽  
Radiation Resistance ◽  
Nuclear Energy ◽  
Extreme Environments ◽  
High Hardness ◽  
Beryllium Oxide ◽  
High Resistivity ◽  
Oxide Material ◽  
Reactor Operation ◽  
Dispersion Phase

Ceramic material is one of the essential materials used in reactors. Beryllium oxide ceramics have good high-temperature radiation stability, high density, high strength, and thermal conductivity at high temperatures, and the price of beryllium oxide is relatively moderate. This makes it more suitable for use as a reflector, moderator, and dispersion phase fuel matrix in a reactor. In recent years, beryllium oxide has attracted widespread attention due to its high hardness, high resistivity, high thermal conductivity, high melting point, and high radiation resistance. Because of its excellent mechanical properties, beryllium oxide materials also have a long history in the field of nuclear energy. Reactor extreme environments have become a significant challenge for optimizing reactor operation and safety performance. The utilization of beryllium oxide can significantly alleviate extreme reactor environments. According to research, the coupling of beryllium oxide material can effectively improve nuclear fuels' thermal conductivity, such as uranium dioxide. Beryllium oxide also has good radiation resistance and neutron scattering properties, which increases its applications in nuclear energy. The article comprehensively reviews the BeO utilization approaches in reactors to improve extreme reactor environments for current reactor operation and future reactor design optimization.

Improvement of Thermal Conductivity of Electroplated Copper Thin-Film Interconnections by Controlling Their Micro Texture

2014 ◽  
Author(s):  
Pornvitoo Rittinon ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Grain Boundaries ◽  
Diffraction Method ◽  
Electron Back Scatter Diffraction ◽  
High Resistivity ◽  
Copper Thin Film ◽  
Electroplated Copper ◽  
The Relationship

Copper thin films are indispensable for the interconnections in the advanced electronic products, such as TSV (Trough Silicon Via), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper. The main reason for the variation can be attributed to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries show very high resistivity and brittle fracture characteristic in the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz’s law. Since the copper interconnections are used not only for the electrical conduction but also for the thermal conduction, it is very important to quantitatively evaluate the crystallinity of the polycrystalline thin-film materials and clarify the relationship between the crystallinity and thermal properties of the films. The crystallinity of the interconnections were quantitatively evaluated using an electron back-scatter diffraction method. It was found that the porous grain boundaries which contain a significant amount of vacancies increase the local electrical resistance in the interconnections, and thus, cause the local high Joule heating. Such porous grain boundaries can be eliminated by control the crystallinity of the seed layer material on which the electroplated copper thin film is electroplated.

The effect of neutron irradiation on the thermal conductivity of beryllium oxide

1963 ◽  
Vol 9 (3) ◽  
pp. 320-326 ◽  
Author(s):  
M.K. Cooper ◽  
A.R. Palmer ◽  
G.Z.A. Stolarski
Keyword(s):  
Thermal Conductivity ◽  
Neutron Irradiation ◽  
Beryllium Oxide

A Study of Developing Composite Material of Penetrated Diamond Particles Into Metal Plate

2009 ◽  
Author(s):  
Keijiro Nishi ◽  
Shigeru Tanaka ◽  
Shigeru Itoh
Keyword(s):  
Thermal Conductivity ◽  
Shock Wave ◽  
Composite Material ◽  
High Speed ◽  
High Hardness ◽  
Optical Microscope ◽  
Metal Plate ◽  
Underwater Shock Wave ◽  
Diamond Particles ◽  
Underwater Shock

An explosive welding technique which uses underwater shock wave to weld thin aluminum plate has been studied and the technical advantages were reported. In this research, we propose a method to produce a composite material using an underwater shock wave generated by detonation of explosive. In the production process, a metal plate (flyer plate) accelerates to a high speed by the underwater shock wave, and collided with diamond particles and penetrated the metal plate. Diamonds were used as the particles and aluminum plates (A1050) as the flyer plates. Diamond has high hardness and excellent thermal conductivity, therefore diamond should provide improvement in the thermal conductivity of the composite material. From recovered sample, the multilayer joined surface including diamond particles was observed using an optical microscope. The production of the pipe of composite materials was attempted using this technique as the application. Details of the experimental methods and results are reported in this paper.

Self-Supporting Nanocrystalline Diamond Foils – A New Concept for Crystalline Diamond on any Technical Surface

2010 ◽  
Vol 438 ◽  
pp. 163-169 ◽  
Author(s):  
Matthias A. Lodes ◽  
Stefan M. Rosiwal ◽  
Robert F. Singer
Keyword(s):  
Thermal Conductivity ◽  
Friction And Wear ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
High Hardness ◽  
Nanocrystalline Diamond ◽  
Temperature Sensitive ◽  
Light Metals ◽  
Temperature Application ◽  
Hot Filament

The manufacturing and application of self-supporting nanocrystalline diamond foils is introduced. The high temperature manufacturing of nanocrystalline diamond foils by hot-filament chemical vapour deposition (HFCVD) is separated from the low temperature application, allowing the coating of temperature sensitive materials, which cannot be coated by HFCVD conventionally. By coating appropriate template materials and stripping-off after the CVD-process, self-supporting, flexible nanocrystalline diamond foils with high hardness (> 70 GPa) and very low thermal conductivity (< 1 W/mK) with thicknesses of up to 100 µm can be produced. Lasercutting is an appropriate method for machining any desired geometry. Thus the possibility to use the extreme properties of diamond for protection against friction and wear on new substrate materials, e.g. steels, light metals and polymers, is generated.

Investigation of Micro-Drilling for Printed Circuit Boards Containing High-Hardness Fillers

2012 ◽  
Vol 565 ◽  
pp. 442-447 ◽  
Author(s):  
Taiji Funabiki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Hiroyuki Kodama
Keyword(s):  
Thermal Conductivity ◽  
Cutting Force ◽  
High Performance ◽  
Printed Circuit Boards ◽  
High Hardness ◽  
High Thermal Conductivity ◽  
Digital Cameras ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Micro Drilling

This paper describes micro-drilling processes for printed circuit boards (PCBs) containing fillers with high hardness and high thermal conductivity. Inspired primarily by devices such as digital cameras, laptop computers, and wireless communications devices, the electronics field today is continuously demanding smaller, lighter, and more technologically advanced high performance devices. However, that the increase in semiconductor-generated heat tends to affect such devices negatively. Additionally, from the viewpoint of environmental problems, electric vehicles and LEDs are being developed actively. PCBs are one of the principal components for building such devices. In recent years, PCBs containing alumina fillers with high thermal conductivity have been developed and begun to be widely used. However, when processing these PCBs, the drill tools become severely worn because of the filler’s high hardness. We therefore examined the drill wear characteristics. The results show the filler is the main factor that causes drill wear, while the increase in cutting force does not affect it. The cutting force increases with the drill wear linearly. Moreover, the characteristic of PCBs with higher filler content rates is close to that of inorganic material like ceramics.

Synthesis, Characterization and Mechanical Properties of Silicon Carbide Nanowires

2010 ◽  
Author(s):  
Huan Zhang ◽  
Weiqiang Ding ◽  
Daryush Aidun
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
High Strength ◽  
Harsh Environments ◽  
Low Density ◽  
Low Thermal Expansion ◽  
Oxidation And Corrosion

Silicon carbide (SiC) material has many outstanding physical and mechanical properties such as high strength, high hardness, low density, high thermal conductivity, low thermal expansion coefficient, large band-gap, and excellent oxidation and corrosion resistances [1–3]. It is a leading material for components and devices operating at high temperature, high power and under harsh environments [4–5]. Micro-sized SiC particles and whiskers are commonly used as reinforcement materials for ceramics, metals and alloys in various structural and tribological applications [6–7].

Trial on C3N4 Coating Cutter Hard-Dry Cutting on Hardened Steel

2010 ◽  
Vol 33 ◽  
pp. 483-486
Author(s):  
Hai Dong Yang ◽  
Xi Quan Xia ◽  
Zhen Hua Qing
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
Tool Material ◽  
High Hardness ◽  
Hardened Steel ◽  
Hard Material ◽  
Low Friction ◽  
Dry Cutting ◽  
Coated Tool

The method of “cutting instead of grinding” on hardened steel is always attractive to engineers. To gain this aim the tool material must first be found. C3N4 is a new kind of super hard material and has comparable properties with diamond in high hardness, wear-resistance, low friction coefficient and thermal conductivity. A number of dry-cutting tests were carried out by C3N4-film coated tool on hardened steel, proved the coating tool is suitable for hard dry cutting.

Development of composite material aluminum-carbon nanotubes with high hardness and controlled thermal conductivity

2019 ◽  
Vol 53 (21) ◽  
pp. 2959-2965 ◽  
Author(s):  
AA Vozniakovskii ◽  
SV Kidalov ◽  
TS Kol'tsova
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Composite Material ◽  
Thermal Properties ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Hardness ◽  
Low Density ◽  
Aluminum Particles ◽  
Chemical Vapor Deposition Growth

The composite material was obtained by chemical vapor deposition growth of carbon nanotubes on the surface of aluminum particles followed by high-temperature compaction under pressure. The content of carbon nanotubes was 1 wt.%. A composite material with a hardness of 58–60 HB, which is two times higher than the hardness of original aluminum with an adjustable thermal conductivity of 50–150 W/(m × K) and with a low density of 2.7 g/cm3 have been obtained. It was found that the hardness and thermal properties could be adjusted depending on the temperature during hot pressing by controlling the formation of Al3C4 carbide.

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