The object of the present invention is such that a surface exchange of metal fine particles by Cu ions, or the like is inhibited in order to prevent formation of Artificial CuS or the like, in extraction and analysis of the metal fine particles (inclusions and precipitates) in a metal material by electrolytic corrosion in a solvent-based electrolytic solution, without significantly changing conventional extraction and analysis methods, and such that the metal deposited on the cathode is actively attached to the cathode so that the deposited metal does not become a contamination source.
An apparatus for electrolytic etching and dissolution and an extraction method for separation and extraction of metal compound particles in a metal material, wherein at least a part of the cathode comprises a material consisting of a metal M′ whose Δ defined by the following formula is 10 or more, and the apparatus comprises an electrolytic cell for containing an electrolytic solution comprising a chemical agent that forms a complex containing the metal M′ and a nonaqueous solvent, Δ = pKsp ⁡ [ M ′ ⁢ x ′ ⁢ Ay ′ ] - pKsp ⁡ [ MxAy ] = ( - log 10 ⁢ Ksp ⁡ [ M ′ ⁢ x ′ ⁢ Ay ′ ] ) - ( - log 10 ⁢ Ksp ⁡ [ MxAy ] ) .