Fabrication of porous aluminum composites containing hollow ceramics

In the molten metal foaming method for fabricating porous aluminum, a thickening agent is added to the molten aluminum to increase its viscosity and to maintain the pores formed in porous aluminum. In this study, hollow ceramics were used as a substitute for the thickening agent. With which we can expect the fabrication of porous aluminum that is lighter than conventional aluminum. We can also expect the fabrication of porous aluminum with a bimodal pore structures, namely, hollow ceramics and pores generated by the foaming agent. With a hand mixer, we attempted to forcibly mix the hollow ceramics with poor wettability with the molten aluminum and to uniformly mix the foaming agent with the molten aluminum. As a result, it was shown that sufficient foaming was obtained when hollow ceramics were added. This suggests that the hollow ceramics have a thickening effect on the molten aluminum and can maintain the pore structures. The scanning electron microscopy of a cross section confirmed that the hollow ceramics did not collapse in the entire porous aluminum.