Influence of Annealing in Vacuum on Dispersion Kinetics of Titanium and Zirconium Nanofilms Deposited onto Oxide Materials

Author(s):  
Y. V. Naidich ◽  
I. I. Gab ◽  
T. V. Stetsyuk ◽  
B. D. Kostyuk ◽  
O. M. Fesenko ◽  
...  
Keyword(s):  
2018 ◽  
Vol 40 (10) ◽  
pp. 1359-1373 ◽  
Author(s):  
Yu. V. Naidich ◽  
◽  
І. І. Gab ◽  
Т. V. Stetsyuk ◽  
B. D. Kоstyuk ◽  
...  
Keyword(s):  

2014 ◽  
Vol 28 (12) ◽  
pp. 973-976
Author(s):  
Yu.V. Naidich ◽  
I.I. Gab ◽  
T.V. Stetsyuk ◽  
B.D. Kostyuk ◽  
O.S. Litvin

2016 ◽  
Vol 37 (9) ◽  
pp. 1225-1237 ◽  
Author(s):  
Yu. V. Naidich ◽  
◽  
І. І. Gab ◽  
Т. V. Stetsyuk ◽  
B. D. Kоstyuk ◽  
...  
Keyword(s):  

2020 ◽  
Vol 21 (2) ◽  
pp. 332-337
Author(s):  
I. I. Gab ◽  
T. V. Stetsyuk ◽  
D. B. Shakhnin

The kinetics of dispersion of thin niobium-copper films deposited onto leucosapphire, alumina and zirconia ceramics and annealed in vacuum at temperatures up to 1100 °C with different exposition times at each temperature (from 5 up to 20 min) was studied. The double films consisted of two layers: the first metallization layer was 150 nm niobium nanofilm deposited onto the oxide surface, and the second copper layer 1,5 mm thick deposited over the first one as a solder was used for joining of metallized oxide samples. It was found that these films remain rather dense during heating up to 1050 °C; and after annealing at 1100 °C they decompose into individual fragments covering about 80% the area of the ceramic substrates even after annealing during 20 min. The kinetic curves for the dispersion of these films were plotted.


Author(s):  
J. F. DeNatale ◽  
D. G. Howitt

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.


Author(s):  
R. J. Lauf

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 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) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.


Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization


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