抄録
The oxidation phenomena of thin films of the reactor-grade pure zirconium and the behavior of thin films of produced zirconia were investigated by means of transmission electron microscopy. The oxidation of zirconium is carried out by electron beam heating in the electron microscope. The results are as follows:
(1) When the specimen is heated gradually, small grains of monoclinic zirconia at first appear in a wide range of the thin film, and then, as a result of the increase in grain number and grain growth, the thin film of zirconium is entirely oxidized. Preferred oxidation near the grain boundary of zirconium is also observed. On the other hand, when the thin film of zirconium is heated strongly, the thin film changes rapidly to the pseudo-amorphous oxide at first, and then the monoclinic zirconia nucleates in the pseudo-amorphous oxide and grows into large grains.
(2) When the thin film of zirconium is oxidized instantaneously in air, the thin film changes into the monoclinic zirconia with a grain size of about 0.3 to 0.5 μ diameter.
(3) In the tetragonal zirconia, an active movement of dislocations and the presence of movable dislocation loops are observed.
