Fabrication of Porous Metals with Directional Pores Through Solidification of Gas-dissolved Melt

摘要

Porous metals with long cylindrical pores aligned in one direction were fabricated by unidirectional solidification using pressurized gas (hydrogen) method (PGM) and thermal decomposition method (TDM). The pores are evolved from insoluble gas when the molten metal dissolving the gas is solidified. In the conventional PGM, the hydrogen pressurized in a high-pressure chamber is used as the dissolving gas. However, the use of high-pressure hydrogen is not desirable because of inflammable and explosive gas, in particular, for scaling up to mass production of lotus metals. In order to overcome this shortcoming, the thermal decomposition method was developed as an alternative simple fabrication method. Gas-forming compounds were added into the molten metal to fabricate lotus metals. The porosity and pore size were controlled by the amount of gas-forming compounds. TDM was applied to fabricate porous copper and aluminium.