Evaluation of porosity in porous copper fabricated by unidirectional solidification under pressurized hydrogen

Lotus-type porous copper with elongated pores has been fabricated by a unidirectional solidification method in a mixture of hydrogen and argon gases with high pressure. The porosity and the pore morphology in the Lotus-type porous copper are significantly affected by the partial pressures of hydrogen and argon. The porosity has been evaluated on the basis of the idea that the gas pores are formed by the insoluble hydrogen during solidification of the liquid copper dissolving hydrogen. The evaluation gives the porosity as a function of the partial pressures of hydrogen and argon. The evaluated values are in good agreement with the experimental results.