| Kinetics of strontium hexaferrite (SrO. 6Fe,O,) formation from
SrCO., and Fe,O, under isothermal conditions were studied by quantitative
X-ray diffraetometry at reaction temperatures of 745, 895,
950 , 984 and 1050 C for various reaction times from 2 minutes to 30
hours. At 745 C, two intermediates, 2SrO.Fe,O and SrO.Fe,O:~
were formed in addition to the final product Sr0.6Fe,03• At higher
temperatures only Sr0.6Fe,03 could be detected. Strontium oxide
(SrO) was not detected at any stage. It was found that although
none of the standard kinetic equations for solid-solid reactions fitted
the experimental data exactly, the trend of the data was to follow the
kinetic equations of phase boundary controlled reactions in the initial
stage, and those of the diffusion controlled reactions in the later stage.
SrCO, and Fe,O,, seemed to react directly, particularly at temperatures
below 1 050 C. |
