Influence of reduction in grain size

An oxidation experiment was carried out in an autoclave at 673K/10.3 MPa and 773K/10.3 MPa. Following different lengths of time in the autoclave, the samples were taken out and analyzed. The microstmctures were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and TEM. 

8 The oxygen content distribution in ZrOj film formed on NC substrate (a) and CG substrate (b).The samples were oxidized for 100 days at 673 K/10.3 MPa. 

9 SEM cross-section images of the oxide formed on (a) NC and (b) CG after a corrosion test for 130 days. 

2 Structural evolution of nanocrystalline zircaloy at high temperature and pressure 

The microstructure of oxide films formed on the NC zircaloy-4 was investigated by TEM. As shown in Fig. 3.10, after 42 days of corrosion, the oxide film was composed solely of tetragonal ZrO (t-Zr02) (see diffraction pattern in 

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