Magnetite (Fe3O4) ferrite magnetic materials have attracted attention arising by the chip
coil electronic material. However, its industrial applications have been limited by the need for high
temperature sintering under reduced pressure or vacuum. In order to develop the process method of
low-cost and energy saving with high-strength and high magnetism of the magnet, in this paper, a new
low-temperature sintering method using CO2 gas and adding a small amount of boric acid (H3BO3) is
proposed. Here, the super fine magnetite powder was fabricated by decomposition from ferrous
oxalate at 500 in CO2 gas. The ferrous oxalate was synthesized using iron chloride and ammonium
oxalate through liquid phase precipitation. The magnetite powder compact was produced by Newton
press and CIP (cold isostatic press) after adding a small amount of boric acid. In this study, the effects
of the additive on the mechanical and magnetic properties of the sintered magnet were also evaluated.
By characteristic evaluation of the magnet, the validity of the proposed new low-temperature sintering
process and the optimal process conditions were confirmed.