Fabrication of Metallic Iron Green Pieces by Colloidal Processing Techniques in Aqueous Media.

Metallic Fe is presented in metal-matrix composites as a feasible material for its use as continuous phase, since it shows very interesting features, such as its low cost, easiness to be recycled and low health risk if compared to other metals, while maintaining its good mechanical properties. In contrast to conventional processing methods in powder metallurgy, that use dry routes or organic media, this work proposes the use of colloidal techniques for processing metallic iron powders. Aqueous suspensions of these powders are proposed to fabricate Fe-based metal-matrix composite materials with homogeneous distribution of the phases. In this work the stability conditions of iron into aqueous suspensions were determined through means of zeta potential measurements and oxidation studies using surfactants. Moreover the influence of the solid contents and the use of additives in the rheological behavior were analyzed. Green compacts have been fabricated by slip-casting of the characterized slurries.