To clarify the rate and mechanism of the formation of Ce-Fe intermetallic compounds by the reduction-diffusion process, two kinds of experiments were carried out;(1) reduction of pellets consisting of CeO
2and CaH
2and (2) reduction-diffusion reaction of pellets consisting of CeO
2, CaH
2and Fe (powder and wire) in the temperature range from 1, 073 to 1, 373 K. X-ray diffraction revealed that the reduction of CeO
2proceeded rapidly in the initial stage of the reaction and then its rate retarded. The reaction progress was not uniform at 1, 073 K; at this temperature Ca is in solid state. In the reduction-diffusion reaction, both compounds of Ce2Fe17 and CeFe2 were formed at 1, 073 and 1, 173 K, though the formation of CeFe
2was not observed in the long time reaction. At 1, 273 K, only Ce
2Fe
17was formed, as expected from the binary phase diagram. The thickness of Ce
2Fe
17layer was in a good agreement with that obtained by the reaction of Fe with a melt of which composition was on the F
e-side liquidus line of the Ce-Fe phase diagram and grew in accordance with a parabolic rate law; the activation energy was 265 kJ·Emol
-1.
抄録全体を表示