having reduction potential higher than that of the first metal is coated in multiple layers on the surfaces of the particles of the first metal first in step a a second mixed solution prepared by mixing a precursor including a second metal with a complexing agent is added to a first mixed solution prepared by mixing particles including a first metal with a reducing agent to form a primary coating layer comprised of the second metal on surfaces of the particles of the first metal also referred to as u201c first metal particles u201d examples of the first metal may include copper nickel tin zinc gold platinum and the like these may be used alone or in combination thereof for example the first metal particles may be copper particles comprised of copper alone or copper nickel alloy particles comprised of copper and nickel the first metal particles may form a core structure in the metal complex of the present invention the reducing agent causes reduction of second metal ions residing in the precursor including the second metal thereby forming a coating layer in which the second metal is coated on the surfaces of the first metal particles the reducing agent may be at least one selected from ascorbic acid hydrazine glucose hydroxylamine and citrate preferably ascorbic acid having a rapid reduction rate for the second metal ions is used as the reducing agent the second metal is preferably at least one selected from silver gold and copper in the metal complex of the invention the second metal may.