Radiation-induced amorphization and swelling in ceramics

Matsunaga, Atsushi; Kinoshita, Chiken; Nakai, Kenta; Tomokiyo, Yoshitsugu

doi:10.1016/0022-3115(91)90123-o

Cited by 62 publications

(24 citation statements)

References 5 publications

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“…However, it should be pointed out that another electron irradiation study found identical amorphization behavior for 0-Sic and a-Sic with the c-axis orientation, with a low-temperature threshold amorphization dose of -0.66 dpa and a critical crystalline-amorphous transition temperature of -300 K [56]. No significant difference between the amorphization behavior of a- MgO have the highest resistance to amorphization of the five materials, followed in order by Al2O3, Si3N4, and Sic.…”

Section: Discussionmentioning

confidence: 90%

Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

Zinkle

Snead

1996

Nuclear Instruments and Methods in Physics Research Section B:

187

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Polycrystalline specimens of alumina (Al2O3), magnesium aluminate spinel (MgA1204), magnesia (MgO), silicon nitride (Si3N4) and silicon carbide (Sic) were irradiated with various ions at temperatures between 200 K and 450 K, and the microstructures were examined following irradiation using cross-section transmission electron microscopy. Amorphization was not observed in any of the irradiated oxide ceramics, despite damage energy densities up to -7 keV/atom (-70 displacements per atom). On the other hand, Sic readily amorphized after damage levels of -0.4 dpa at room temperature. Silicon nitride exhibited intemediate behavior; . irradiation with Fe* ions at room temperatm produced amorphization in the implanted ion region after damage levels of -1 dpa. However, irradiated regions outside of the implanted ion region did not amorphize even after damage levels in excess of 5 dpa. The amorphous layer in the Fe-implanted region of Si3N4 did not appear if the specimen was simultaneously irradiated with 1 MeV He+ ions at room temperature. By comparison with published results, it is concluded that the implantation of certain chemical species has a pronounced effect on the amorphizahon threshold dose of all five materials. Intense ionizing d a t i o n inhibits amorpkation in Si3N4, but does not appear to signtficantly influence the amorphimion behavior of Sic.

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Section: Discussionmentioning

confidence: 90%

Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

Zinkle

Snead

1996

Nuclear Instruments and Methods in Physics Research Section B:

187

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“…Elevated temperature neutron irradiations of AIN [6,7] and SilN4 [8] have observed faulted dislocation loops on basal and prism habit planes, respectively. Am:rphization did not occur during 1 MeV electron irradiation at 140 K up to a fluence of 3x102b/m-(-0.5 d~a) in AIN [9] or during 1-2 MeV electron irradiation at 100-170 K up to fluences of 3-18x10zb/m-(-0.5-4 dpa) in SilNJ [9][10][11]. AIN and Si~N~were found to remain crystalline following room temperature bombardment with 3 MeV Kr ions up to a fluence of 2x102'/m~(-150 dpa peak damage) [12].…”

Section: Introductionmentioning

confidence: 88%

Effect of Low Temperature ion Irradiation on the Microstructure of Nitride Ceramics

Zinkle¹,

Snead²,

Eatherly³

et al. 1998

MRS Proc.

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Cross-section transmission electron microscopy was used to investigate the microstructure of polycrystalline silicon nitride (Si~NJ) and aluminum nitride (AIN) following 2 MeV Si ion irradiation at 80 and 400 K up to a fluence of 4x1020 ions/mz (maximum damage of -10 displacements per atom, dpa). A buried amorphous band was observed at both temperatures in Si~NA in the region corresponding to the peaks in the implanted ion and displacement damage. From a comparison of Si~NJ specimens irradiated at different fluences, it is concluded that the amorphization is primarily controlled by the implanted Si concentration rather than the displacement damage level. SiJNi amorphization did not occur in regions well-separated from the implanted ions for doses up to at least 3 dpa at 80 K, whereas amorphization occurred in the ion implanted region (calculated Si concentration >0.01 at.%) for damage levels as low as -0.6 dpa. The volumetric swelling associated with the amorphization of SijN~is c 10%. Amorphization was not observed in any of the irradiated AIN specimens. A moderate density of small (-3 nm) defect clusters were observed in the crystalline damaged regions of both the S i~N$ and AIN specimens at both irradiation temperatures. Aligned network dislocations were also observed in the AIN specimen irradiated to high dose at 80 K.

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“…Above the critical temperature the SiC remains crystalline although point defects are created by the irradiation resulting in significant strain in the substrate. The critical temperature and critical fluence for amorphization are independent of the crystal polytype [126,131,132]. Wendler at al.…”

Section: Amorphizationmentioning

confidence: 99%

“…There are two radioactive iodine isotopes. One of the isotopes is 131 I has a half life of only about 8 days but with a biological half life of approximately 140 days. 129 I, is the other isotope and has a half life of 15.7 million years.…”

Section: Iodine Diffusionmentioning

confidence: 99%

“…The other group are the fission products which leak out off the TRISO particle causing a radiological danger. The most important of these are m 110 Ag, 134 I, 131 Cs and 137 Cs, 90 Sr, 88 Kr and 133 Xe with the following somewhat less important fission products 132 Te, 140 La and the actinide 239 Pu [23,24,25]. In the last section of the paper ( §4) this review will concentrate only on some of the important elements, for the topics of the other sections, specific elements are not really of importance.…”

Section: Introductionmentioning

confidence: 99%

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Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

100

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A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for Triple Coated Isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutron or bombardment at substrate temperatures above 350°C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950°C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

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Radiation-induced amorphization and swelling in ceramics

Cited by 62 publications

References 5 publications

Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

Effect of Low Temperature ion Irradiation on the Microstructure of Nitride Ceramics

Diffusion of fission products and radiation damage in SiC

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