Coral-like iron particles synthesized by morphology controllable reduction process

Abstract

This paper reports a novel synthesis of iron (Fe) powders in which high-purity and controlled primary and secondary assembled particles can be produced at low cost with safe process. Iron hydroxide powder precursors with fine-sized and acicular morphology were prepared and then reduced at an optimum temperature under reducing atmosphere by using single-step and two-step reduction. In the case of two-step reduction, the precursor powders were reduced by using a hydrogen/argon mixed gas for 1.5h with a subsequent second reduction using higher hydrogen/argon mixed gas for 2h. The morphology of the Fe powders strongly depends on the reduction conditions and precursor's morphology. The two-step reduced powders had pure iron powders with large elongated shape and porous sponge-like interlocking structure. The synthesized Fe powders were mixed with KClO4 and the pyrotechnic performance was examined. It is found that metal powder prepared by using two-step reduction is very suitable for producing porous sponge-like microstructure and for pyrotechnic applications.