Abstract
Hexagonal $\delta$-FeOOH was coated with Ba-Sol, which was produced by hydrolizing Ba(OC2H5)2, Ba-Sol coated $\delta$-FeOOH spread on a stainless plate, dried at 8$0^{\circ}C$ and then heat-treated. In this way, Ba-ferrite fine particles were produced. although there was a difference in a degree of hydrolysis of Ba(OC2H5)2, crystalline phase of Ba-ferrite appeared around 617$^{\circ}C$, and Ba-ferrite single phase was obtained after heat treatment at 80$0^{\circ}C$ for 2 hr. When Ba-ferrite was made from Ba-Sol coated $\delta$-FeOOH, $\delta$-FeOOH was thermally decomposed to $\alpha$-Fe2O3 at $700^{\circ}C$, producing a porous structure which was observed by TEM photographs. But the porous structure was not observed at 80$0^{\circ}C$. Ba-ferrite, heat-treated at 80$0^{\circ}C$ for 2 hr, had mean particle size of 1000$\AA$, lattice parameter of a0=5.889243 $\AA$ and c0=23.214502 $\AA$, a saturation magnetization ($\sigma$8) of 45.3 emu/g and a coercive force (Hc) of 5200Oe.
