Structure of pyrocarbon and silicon carbide coatings of micro fuel elements

1988 ◽  
Vol 64 (2) ◽  
pp. 107-112
Author(s):  
A. S. Chernikov ◽  
T. A. Mireev ◽  
V. V. Teslenko ◽  
S. D. Kurbakov ◽  
L. I. Mikhailichenko ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Carbide Coatings ◽  
Fuel Elements

FORMATION OF SILICON CARBIDE COATINGS BY CHEMICAL VAPOR DEPOSITION (review). Part 1

2021 ◽  
pp. 100-111
Author(s):  
D.V. Sidorov ◽  
◽  
A.A. Schavnev ◽  
A.A. Melentev ◽  
◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Point Of View ◽  
Technological Parameters ◽  
Technical Literature ◽  
Pure Silicon ◽  
Carbide Coatings ◽  
Complex Process

The article provides an overview of the scientific and technical literature in the field of the formation of silicon carbide coatings by chemical vapor deposition (CVD). CVD is a complex process, approaches to which vary depending on the tasks being solved. Depending on the technological parameters, the initial reagents, the substrate for deposition, the type and design of the CVD reactors, it is possible to achieve both the deposition of pure silicon carbide and the co-deposition of silicon and/or carbon. In the first part of the article, attention is paid to the study of CVD from the point of view of the mechanisms of chemical reactions, the design of the deposition apparatus, the substrates for deposition.

Grain-boundary type and distribution in silicon carbide coatings and wafers

2018 ◽  
Vol 500 ◽  
pp. 176-183 ◽  
Author(s):  
Felix Cancino-Trejo ◽  
Eddie López-Honorato ◽  
Ross C. Walker ◽  
Romelia Salomon Ferrer
Keyword(s):  
Silicon Carbide ◽  
Grain Boundary ◽  
Boundary Type ◽  
Carbide Coatings

Direct Assay for Molybdenum and Ruthenium in Uranium Alloys by X-Ray Emission Spectrometry

1957 ◽  
Vol 1 ◽  
pp. 387-398 ◽  
Author(s):  
D. S. Flikkema ◽  
R. V. Schablaske
Keyword(s):  
Silicon Carbide ◽  
Analytical Procedure ◽  
Flat Surface ◽  
Emission Lines ◽  
Emission Spectrometry ◽  
Chemical Dissolution ◽  
X Ray ◽  
Direct Assay ◽  
Uranium Fuel ◽  
Fuel Elements

AbstractIt has been found possible to determine quickly the concentrations of molybdenum and ruthenium in non-radioactive alloys representative of high burn-up reactor fuels by the method of X-ray emission spectrometry. Preliminary steps of chemical dissolution and separation are not required. The alloys, essentially ternaries of molybdenum and ruthenium with uranium, are being studied because they are considered to typify the alloys which will result from cycling uranium fuel elements through the sequence of fabrication, use and pyro.metallurgical processing.The analytical procedure involves sampling of the ingot by slicing with a silicon carbide wheel at the plane of interest and reducing the surface to the flatness and finish obtained by a five-minute grinding and polishing operation. In the X-ray spectrograph the flat surface is examined for the intensities of its molybdenum and ruthenium K emission lines, with counting times of one to eight minutes. Calibration plots of intensity versus chemically determined weight per cent are established and used for subsequent sets of analyses.

Low-Temperature PACVD Silicon Carbide Coatings

1991 ◽  
Vol 250 ◽  
Author(s):  
W. Halverson ◽  
G. D. Vakerlis ◽  
D. Garg ◽  
P. N. Dyer
Keyword(s):  
Silicon Carbide ◽  
Low Temperature ◽  
Large Volume ◽  
Chemical Vapor ◽  
Reaction Chamber ◽  
Metallic Substrates ◽  
3 Dimensional ◽  
Carbide Coatings ◽  
Reactor Operating ◽  
Wear Tests

AbstractPlasma-assisted chemical vapor deposition (PACVD) is used extensively to coat planar (2-dimensional) substrates. In principle, the technique can be used to deposit coatings on 3-dinensional objects. However, extending PACVD to coat 3-dimensional objects uniformly requires careful control of the plasma, substrate temperature, and reactant concentrations over a large volume. A novel low-temperature radio frequency PACVD reactor design was developed to deposit coatings uniformly and reproducibly on 3-dimensional metallic substrates. The design features a temperature-controlled reaction chamber fitted with one or more rf-driven electrodes to generate uniform, large-volume plasma. The reactor was used to develop a series of silicon carbide coatings, which were deposited at or below 500°C. The coatings contain SiC and varying amounts of free silicon and/or amorphous carbon (diamond-like carbon), depending on reagent gas composition and reactor operating parameters. The coatings significantly reduced wear on stainless steel samples in ball-on-disk and abrasive wear tests and provided oxidation protection to molybdenum and titanium alloy.

Ceramic Coatings on Graphite via Polymer Vapor Pyrolysis Deposition Process

2008 ◽  
Vol 368-372 ◽  
pp. 1297-1299
Author(s):  
Xin Xing ◽  
Lin Liu ◽  
Xiao Zhong Huang ◽  
Xiao Dong Li
Keyword(s):  
Molecular Weight ◽  
Silicon Carbide ◽  
Pyrolysis Temperature ◽  
Deposition Process ◽  
Ceramic Coatings ◽  
Low Molecular Weight ◽  
Carbide Coatings ◽  
N2 Atmosphere ◽  
Amorphous Sic ◽  
Sic Coatings

Silicon carbide coatings on graphite were prepared through polymer vapor pyrolysis deposition process (PVPD) under N2 atmosphere. During this process, some low molecular weight substances that polycarbosilane (PCS) pyrolyzed can be deposited on graphite, and they can convert into SiC in high temperature. The results of XRD showed that amorphous SiC coatings were formed on graphite when the pyrolysis temperature was 1000°C, andβ-SiC phase formed in the coatings when the temperature up to 1250°C. Effects of the coatings on the microstructure and properties were investigated. It was shown that the uniform dense SiC coatings could be obtained by carefully controlling the pyrolysis temperature and ramping rate when the number molecular weight of PCS was in the range of 1,000~1,500.

Control of stoichiometry, microstructure, and mechanical properties in SiC coatings produced by fluidized bed chemical vapor deposition

2008 ◽  
Vol 23 (6) ◽  
pp. 1785-1796 ◽  
Author(s):  
E. López-Honorato ◽  
P.J. Meadows ◽  
J. Tan ◽  
P. Xiao
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Young’S Modulus ◽  
Fluidized Bed ◽  
Vapor Deposition ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Carbide Coatings ◽  
Fuel Particles

Stoichiometric silicon carbide coatings the same as those used in the formation of TRISO (TRistructural ISOtropic) fuel particles were produced by the decomposition of methyltrichlorosilane in hydrogen. Fluidized bed chemical vapor deposition at around 1500 °C, produced SiC with a Young’s modulus of 362 to 399 GPa. In this paper we demonstrate the deposition of stoichiometric silicon carbide coatings with refined microstructure (grain size between 0.4 and 0.8 μm) and enhanced mechanical properties (Young’s modulus of 448 GPa and hardness of 42 GPa) at 1300 °C by the addition of propene. The addition of ethyne, however, had little effect on the deposition of silicon carbide. The effect of deposition temperature and precursor concentration were correlated to changes in the type of molecules participating in the deposition mechanism.

scholarly journals Irradiation performance of pyrolytic silicon carbide coatings on fissile fuel particles

1984 ◽  
Vol 42 ◽  
pp. 418-419
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Product ◽  
Fission Products ◽  
Carbide Coatings ◽  
Fuel Particles ◽  
Irradiation Performance ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of

Fuel particles for the High Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC coating with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) the combined effects of irradiation and fission product interactions. This paper reports the behavior of SiC deposited on fissile fuel particles and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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