Papers by Keyword: Radiation Enhanced Diffusion

Abstract: Paper presents the results of the growth rate of the interaction layer of uranium-molybdenum dispersed fuel in aluminum matrix and influence of silicon alloying on it. The growth process of amorphous interaction layer depends on the radiation diffusion which is proportional to the fission rate in the power of 1⁄4. The alloying of the matrix by silicon does not lead to a change in the mechanism and kinetics of the interaction layer growth, but only slows it down.

Abstract: The surface properties of W-implanted H13 steel are investigated using pulse multi-charged ion implantation. Computer simulations based on the binary collision approximation, TRIDYN, have been applied to calculate the concentration depth profiles of implanted tungsten ions in H13 steel. The calculated result by TRIDYN program is compared with that from experimental results. The factors affecting the surface properties of W-implanted H13 steel have been discussed. The radiation enhanced diffusion induced by spike is the main factor affecting the concentration depth profile. Compared with single energy ion implantation, the multi-charged ion implantation will make the concentration gradient become small, which is conducive to the formation of a kind of relatively uniform surface structure, and further improve the wear resistance of H13 steel.

Abstract: Low-temperature diffusion of Cr, Mo, Ni, Pd, Pt, and V in silicon diodes is compared in the range 450 - 800 oC. Before the diffusion, the diodes were implanted with high-energy He2+ to assess, if the radiation defects enhance the concentration of metal atoms at electrically active sites and what is the application potential for carrier lifetime control. The devices were characterized using AES, XPS, DLTS, OCVD carrier lifetime and diode electrical parameters. The metal atoms are divided into two groups. The Pt, Pd and V form deep levels in increased extent at the presence of radiation defects above 600 oC, which reduces the excess carrier lifetime. It is shown as a special case that the co-diffusion of Ni and V from a NiV surface layer results fully in the concentration enhancement of the V atoms. The enhancement of the acceptor level V-/0 (EC 0.203 eV) and donor level V0/+ (EC 0.442 eV) resembles the behavior of substitutional Pts. The second group is represented by the Mo and Cr. They easily form oxides, which can make their diffusion into a bulk more difficult or impossible. Only a slight enhancement of the Cr-related deep levels by the radiation defects has been found above 700 oC.

Abstract: In this conference we try to give a survey of the main characteristics of aging of oxides under irradiation in the perspective of the recent developments of the ab-initio modeling capabilities. After a brief recall of the relevant radiation – matter interactions, we present the main aspects of materials aging under irradiation, I) defect creation either elastically or inelastically, ii) microstructure evolution due to defect elimination, iii) radiation enhanced diffusion, iv) phase changes under irradiation.