Development of new foaming agent for metal foam

Abstract

The study of metallic foams has become attractive to researchers interested in both scientific and industrial applications. The different production methods have not been widely utilized because of difficult process control and high production costs. A new easily-available agent for metal foaming, calcium carbonate, is suggested in this work. An established ion-exchange method was employed for a novel purpose - the coating of calcium carbonate powder with fluoride for wettability enhancement. Effect of coating was considered by the examination of wetting behavior of coated and uncoated CaCO3 by the Al melt. It was determined that coated carbonate produced metallic foam with density comparable to that of samples treated by titanium hydride (∼ 1 × 103 kg·m-3) and much less then the density of samples obtained by uncoated carbonate (1.7 × 103 kg·m-3). It was also observed that coated carbonate ensured aluminum foam with smaller pores (1.1 × 10-3 m) than when the conventional foaming agent, titanium hydride, is used (1.8 × 10-3 m). The present study shows that calcium carbonate is highly applicable to foamed metal production.