To provide a porous metal having a size of voids of ≤1 mm and a void fraction of ≥60% for which only limited production methods were available in the conventional technique, and to provide the method of producing the same.
Metal powder comprising one or more components is sealed together with a gas of a pressure equal to or greater than the atmospheric pressure into the inside of a metallic vessel which can be plastically worked. The metallic vessel is pressurized at a high temperature to sinter the metal powder and to compress the gas. Next, the sintered compact comprising the high pressure gas is heated to a solid-liquid two phase state, and the volume of the gas in a solid-liquid two phase state is expanded to form voids. Thus, the porous metal comprising voids of ≤1 mm and having a void fraction of ≥60% is produced.