Abstract
Samples used in this experiment are as follows.
(1) UO2 powder : Ceramic grade UO2 powder produced by Degussa Works. (o/u-2.08)
(2) Massive UO2: Eleetrodeposited UO2. (o/u-2.005)
(3) Massive UO2: Fused UO2 produced by Spencer Works. (o/u-2.00 3)
(4) Massive U4O9 : Electrodeposited U4O9_X (o/u-2.10)
(All massive samples were crushed -325 mesh and tested)
The difference of oxidation behavior of each sample was detected by X-ray analysis, in-frared spectrophotometry, D.T.A. and microstructure.
Main results obtained were as follows.
1) The relationship between heating temperature and o/u ratio of samples were shown in Fig.3. The results of X-ray analysis and infrared spectrophotometry of these heated samples were summarized in Table 2. The DTA curves of these samples ware shown in Fig.1. From these results, it seemed that the oxidation behavior of these samples were same substantially, namely, UO2 (cubic) or U4O9_X (cubic) 200-400°C U3O7 (tetragonal) 340-425°C U3O8 (orthorhombic), and the difference of the crystal transformation temperature of individual sample might be introduced from its particle size and surface activity.
2) From the results of infrared spectrophotometry, we could recognize a small absorption at about 15.3μ of infrared ray, and it might be caused by the existence of U3O7 phase.
3) As shown in Photo. 2, the shape of electrodeposited U4O9_X single crystal was lozenge and very thin, and completely differ from the shape of octahedron of electrodeposited UO2. But this apparent difference of both crystals are not so substantial. The regular triangular etch pits on the lozenge face of U4O9_X crystal showed that this face is identical with (111) face of UO2 crystal.
