Abstract
Fine composite particles containing yttrium and iron were prepared from homogeneous solution using urea as a precipitant generator. The ratio of yttrium to iron in the precipitate could be controlled by adjusting the concentration of the starting materials in the initial solution. These composite particles were considered to be amorphous. Shapes and morphology of the precipitated particles were influenced by the difference of the reaction conditions. Particles obtained from the solution containing 1.88 mmol dm-3 FeCl3 H2O, 3.13 mmol dm-3 YCl3 H2O and 500 mmol dm-3 urea at 97 °C were almost spherical and mono-dispersed. Particles precipitated on the condition as mentioned above converted from amorphous into monophasic garnet (Y3Fe5O12) by calcining at 1,200 °C for 5 hours. After calcination, particle changed its color from brown to medium olive and indicated marked magnetic character.
