Neutron Irradiation, Amorphous Transformation and Agglomeration Effects on the Permittivity of Nanocrystalline Silicon Carbide (3C-SiC)

NANO ◽  
2018 ◽  
Vol 13 (03) ◽  
pp. 1830002 ◽  
Author(s):  
Elchin M. Huseynov
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
Neutron Irradiation ◽  
Nanocrystalline Silicon ◽  
Dielectric Polarization ◽  
Transmission Electron ◽  
Before And After ◽  
Agglomeration Effects ◽  
Temperature Ranges ◽  
Nanocrystalline Silicon Carbide

Nanocrystalline 3C-SiC is irradiated by neutron flux ([Formula: see text][Formula: see text]n/cm2s) up to 20[Formula: see text]h in the TRIGA Mark II type research reactor. At the first stage, silicon carbide nanoparticles were analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM) devices before and after neutron irradiation. Amorphous transformation and agglomeration effects on the permittivity of nanocrystalline silicon carbide (3C-SiC) were comparisons investigated before and after neutron irradiation. Dielectric spectroscopies of nanocrystalline 3C-SiC have been conducted at the frequency ranges of 0.1[Formula: see text]Hz–2.5[Formula: see text]MHz and temperature ranges of 100–400[Formula: see text]K. Real and imaginary parts of the permittivity of the nanomaterial were analyzed for comparison before and after neutron irradiation. Neutron irradiation increased dopant elements concentration in the nanocrystalline 3C-SiC particles, and that directly affects dielectric polarization and increased permittivity. All the mechanisms of the observed effects are given in the work.

Permittivity-Frequency Dependencies Study of Neutron-Irradiated Nanocrystalline Silicon Carbide (3C-SiC)

NANO ◽  
2017 ◽  
Vol 12 (06) ◽  
pp. 1750068 ◽  
Author(s):  
Elchin M. Huseynov
Keyword(s):  
Neutron Irradiation ◽  
Element Concentration ◽  
Nanocrystalline Silicon ◽  
Dielectric Polarization ◽  
Sic Particles ◽  
Before And After ◽  
Temperature Ranges ◽  
Flux Formula ◽  
Nanocrystalline Silicon Carbide ◽  
Dopant Element

Nanocrystalline 3C-SiC was irradiated by neutron flux ([Formula: see text] n[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]s[Formula: see text] up to 20[Formula: see text]h in the TRIGA Mark II type research reactor. The experiments have been conducted in the 0.1[Formula: see text]Hz–2.5[Formula: see text]MHz frequency and 100–400[Formula: see text]K temperature ranges. The frequency dependencies of real and imaginary parts of the permittivity of nanomaterial were analyzed comparatively before and after neutron irradiation. After neutron irradiation, there was increase in dopant element concentration in the nanocrystalline 3C-SiC particles. Concentration of new dopant elements in the 3C-SiC nanomaterial directly affects dielectric polarization and leads to increased permittivity. Simultaneously, after neutron irradiation, agglomeration and amorphous transformation influence on the polarization of nanocrystalline 3C-SiC. Moreover, 3C-SiC nanoparticle interface polarization gives rise to dispersion. It was found that ionic polarization was dominant in the nanocrystalline 3C-SiC particles.

Behaviour of Nanocrystalline Silicon Carbide Under Low Energy Heavy Ion Irradiation

2009 ◽  
Vol 1215 ◽  
Author(s):  
Dominique Gosset ◽  
Laurence Luneville ◽  
Gianguido Baldinozzi ◽  
David Simeone ◽  
Auregane Audren ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Grain Size ◽  
Ion Irradiation ◽  
Healing Process ◽  
Grazing Incidence ◽  
Nanocrystalline Silicon ◽  
Heavy Ion ◽  
Before And After ◽  
Gen Iv ◽  
Nanocrystalline Silicon Carbide

AbstractSilicon carbide is one of the most studied materials for core components of the next generation of nuclear plants (Gen IV). In order to overcome its brittle properties, materials with nanometric grain size are considered. In spite of the growing interest for nano-structured materials, only few experiments deal with their behaviour under irradiation. To assess and predict their evolution under working conditions, it is important to characterize their microstructure and structure. To this purpose, we have studied microcrystalline and nanocrystalline samples before and after irradiation at room temperature with 4 MeV Au ions. In fact, it is well established that such irradiation conditions lead to amorphisation of the material, which can be restored after annealing at high temperature. We have performed isochronal annealings of both materials to point out the characteristics of the healing process and eventual differences related to the initial microstructure of the samples. To this purpose Grazing Incidence X-Ray Diffraction has been performed to determine the microstructure and structure parameters. We observe the amorphisation of both samples at similar doses but different annealing kinetics are observed. The amorphous nanocrystalline sample recovers its initial crystalline state at higher temperature than the microcrystalline one. This effect is clearly related to the initial microstructures of the materials. Therefore, the grain size appears as a key parameter for the structural stability and mechanical properties of this ceramic material under irradiation.

An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films

1973 ◽  
Vol 31 ◽  
pp. 32-33 ◽  
Author(s):  
T. C. Tisone ◽  
S. Lau
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Thermally Grown Oxide ◽  
Ion Milling ◽  
Compound Formation ◽  
Technology Application ◽  
Transmission Electron ◽  
Before And After ◽  
Au Thin Films

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.

Attritious Wear of Silicon Carbide

1976 ◽  
Vol 98 (4) ◽  
pp. 1125-1134 ◽  
Author(s):  
R. Komanduri ◽  
M. C. Shaw
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
High Temperature ◽  
High Speed ◽  
Layer By Layer ◽  
Wear Area ◽  
Work Material ◽  
Transmission Electron ◽  
Metal Silicides ◽  
Boundary Fracture

Attritious wear of silicon carbide in simulated grinding tests against a cobalt base superalloy at high speed and extremely small feed rate was studied using a scanning electron microscope (SEM) and an auger electron spectroscope (AES). In many cases the wear area of silicon carbide was found to be concave rather than planar in shape. Several microcracks and grain boundary fracture were also observed. No evidence of metal build-up was observed on silicon carbide which was not the case with aluminum oxide. AES study of the rubbed surface on the work material and transmission electron microscope (TEM) investigation of the wear debris suggest that attritious wear of silicon carbide is due to one or more of the following mechanisms: 1 – Preferential removal of surface atoms on the abrasive, layer by layer, by oxidation under high temperature and a favorably directed shear stress; 2 – disassociation of silicon carbide at high temperature and (a) diffusion of silicon into the work material and formation of metal silicides and (b) diffusion of carbon into the work material and formation of unstable metal carbides (in the present case Ni3C and Co3C) which decompose during cooling to metal and carbon atoms; 3 – pinocoidal cleavage fracture of silicon carbide on basal planes c(0001) resulting in the removal of many micron-sized crystallites.

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