| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively produce foams of high melting materials (metals and ceramics) having excellent lightness in weight, air permeability and filtration characteristic and uniformly distributed spherical pores. SOLUTION: Metals or ceramics are melted in a melting furnace to obtain molten metal. Gases consisting of at least one kind of gases among gaseous hydrogen, nitrogen and oxygen, are applied to this molten metal and the total pressure 1 to 500atm of the gases is applied thereto to dissolve the gases. Casting molds are preheated to the respective m.p. of the metals and ceramics -200 deg.C to +50 deg.C. While the total pressure of the gases applied to the molten metal is maintained, the molten metal is poured into the casting molds preheated to the temp. described above. While the casting molds are cooled from at least one directions of the upper part, the lower part and the flank parts in the state of maintaining the total pressure of the gases applied to the molten metal, the molten metal is solidified under stirring so as to attain the uniform molten metal temp., by which the spherical pores of porosity of 50 to 98% and a diameter of 5μm to 10mm are uniformly dispersed into the molten metal. Further, fine particles to constitute the nuclei for foaming are added to the molten metal.
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