The method of producing a solid spherical powder according to the present disclosure includes: a step A of preparing a first powder raw material containing agglomerated particles and/or solidified particles having a particle diameter of 1 μm to 1,000 μm and introducing the first powder raw material into a plasma flame to produce a hollow spherical powder having a surface layer shell having a thickness of 1 μm to 50 μm; a step B of subjecting the hollow spherical powder to pulverization treatment to pulverize a hollow shape of the hollow spherical powder, thus obtaining a second powder raw material which is solid; and a step C of introducing the second powder raw material into a plasma flame, melting and solidifying the second powder raw material to obtain the solid spherical powder.

The method of producing a solid spherical powder according to the present disclosure includes: a step A of preparing a first powder raw material containing agglomerated particles and/or solidified particles having a particle diameter of 1 μm to 1,000 μm and introducing the first powder raw material into a plasma flame to produce a hollow spherical powder having a surface layer shell having a thickness of 1 μm to 50 μm; a step B of subjecting the hollow spherical powder to pulverization treatment to pulverize a hollow shape of the hollow spherical powder, thus obtaining a second powder raw material which is solid; and a step C of introducing the second powder raw material into a plasma flame, melting and solidifying the second powder raw material to obtain the solid spherical powder.

A method for preparing copper-solver and copper-gold porous microsheets with specific pore sizes, the method including the steps of providing a solution of copper microsheets and adding a silver or gold solution under controlled temperature, the reaction conditions can be changed to determine pore sizes.

A method for preparing copper-solver and copper-gold porous microsheets with specific pore sizes, the method including the steps of providing a solution of copper microsheets and adding a silver or gold solution under controlled temperature, the reaction conditions can be changed to determine pore sizes.

While a water reaction system containing silver ions is irradiated with ultrasonic waves to cause cavitation therein, a reducing agent containing solution, which contains an aldehyde as a reducing agent, is mixed with the water reaction system to deposit silver particles, the solid-liquid separation of which is carried out, and thereafter, the separated silver particles are washed and dried to produce a spherical silver powder which has a closed cavity in each particle thereof.

While a water reaction system containing silver ions is irradiated with ultrasonic waves to cause cavitation therein, a reducing agent containing solution, which contains an aldehyde as a reducing agent, is mixed with the water reaction system to deposit silver particles, the solid-liquid separation of which is carried out, and thereafter, the separated silver particles are washed and dried to produce a spherical silver powder which has a closed cavity in each particle thereof.

A lightweight, selectively degradable composite material is disclosed. The composite material comprises a compacted powder mixture of a first powder, the first powder comprising first metal particles comprising Mg, Al, Mn, or Zn, or an alloy of any of the above, or a combination of any of the above, having a first particle oxidation potential, a second powder, the second powder comprising low-density ceramic, glass, cermet, intermetallic, metal, polymer, or inorganic compound second particles, and a third metal powder, the third metal powder comprising third metal particles having an oxidation potential that is different than the first particle oxidation potential. The compacted powder mixture has a microstructure comprising a matrix comprising the first metal particles, the second particles and third particles dispersed within the matrix, the third particles comprising a network of third particles extending throughout the matrix, the composite material having a density of about 3.5 g/cm.sup.3 or less.

A method for preparing copper-solver and copper-gold porous microsheets with specific pore sizes, the method including the steps of providing a solution of copper microsheets and adding a silver or gold solution under controlled temperature, the reaction conditions can be changed to determine pore sizes.

A method for preparing copper-solver and copper-gold porous microsheets with specific pore sizes, the method including the steps of providing a solution of copper microsheets and adding a silver or gold solution under controlled temperature, the reaction conditions can be changed to determine pore sizes.

Methods for forming nanostructures of various shapes are disclosed. Nanocubes, nanowires, nanopyramids and multiply twinned particles of silver may by formed by combining a solution of silver nitrate in ethylene glycol with a solution of poly(vinyl pyrrolidone) in ethylene glycol. Hollow nanostructures may be formed by reacting a solution of solid nanostructures comprising one of a first metal and a first metal alloy with a metal salt that can be reduced by the first metal or first metal alloy. Nanostructures comprising a core with at least one nanoshell may be formed by plating a nanostructure and reacting the plating with a metal salt.