Composition for direct-current cathodic electrolysis, lubrication-film-equipped metal material, and production method therefor

Abstract

A composition for direct-current cathodic electrolysis. The composition is capable of forming a lubrication-film-equipped metal material exhibiting excellent lubrication properties and excellent chemical conversion properties after degreasing. This composition for direct-current cathodic electrolysis includes: (A) at least one metal ion selected from the group consisting of typical metal ions (excluding zinc ion) having a valency of at least 2 and rare-earth-element ions, or a complex thereof; (B) an organic acid compound including, in the molecule thereof, a carboxyl group, and a straight-chain alkylene group having at least 4 carbon atoms; and (C) water.

1 - 8 . (canceled) 
     
     
         9 . A composition for direct-current cathodic electrolysis, comprising:
 (A) at least one type of metal ion, or its complex, selected from the group consisting of divalent or higher valent main group metal ions (excluding zinc ion) and rare earth element ions;   (B) an organic acid compound having a carboxyl group and a linear alkylene group with 4 or more carbon atoms per molecule; and   (C) water.   
     
     
         10 . The composition for direct-current cathodic electrolysis according to  claim 9 , wherein the metal ion or its complex (A) includes at least one type of metal ion, or its complex, selected from the group consisting of magnesium ion, calcium ion, aluminum ion, yttrium ion and lanthanoid metal ions. 
     
     
         11 . The composition for direct-current cathodic electrolysis according to  claim 9 , wherein the organic acid compound (B) includes an aliphatic monocarboxylic acid having a linear alkylene group with 4 or more carbon atoms or an aliphatic dicarboxylic acid having a linear alkylene group with 4 or more carbon atoms. 
     
     
         12 . The composition for direct-current cathodic electrolysis according to  claim 10 , wherein the organic acid compound (B) includes an aliphatic monocarboxylic acid having a linear alkylene group with 4 or more carbon atoms or an aliphatic dicarboxylic acid having a linear alkylene group with 4 or more carbon atoms. 
     
     
         13 . The composition for direct-current cathodic electrolysis according to  claim 9 , having a pH of 3.5 to 12.5. 
     
     
         14 . The composition for direct-current cathodic electrolysis according to  claim 10 , having a pH of 3.5 to 12.5. 
     
     
         15 . The composition for direct-current cathodic electrolysis according to  claim 11 , having a pH of 3.5 to 12.5. 
     
     
         16 . The composition for direct-current cathodic electrolysis according to  claim 12 , having a pH of 3.5 to 12.5. 
     
     
         17 . A method of producing a metal material having a lubricating film, comprising a step of forming a lubricating film on a surface of a metal material by immersing the metal material in a composition for direct-current cathodic electrolysis and performing cathodic electrolysis using direct current with the metal material serving as a cathode,
 wherein the composition for direct-current cathodic electrolysis includes:   (A) at least one type of metal ion, or its complex, selected from the group consisting of divalent or higher valent main group metal ions (excluding zinc ion) and rare earth element ions;   (B) an organic acid compound having a carboxyl group and a linear alkylene group with 4 or more carbon atoms per molecule; and   (C) water.   
     
     
         18 . The method of producing a metal material having a lubricating film according to  claim 17 , wherein the metal ion or its complex (A) includes at least one type of metal ion, or its complex, selected from the group consisting of magnesium ion, calcium ion, aluminum ion, yttrium ion and lanthanoid metal ions. 
     
     
         19 . The method of producing a metal material having a lubricating film according to  claim 17 , wherein the organic acid compound (B) includes an aliphatic monocarboxylic acid having a linear alkylene group with 4 or more carbon atoms or an aliphatic dicarboxylic acid having a linear alkylene group with 4 or more carbon atoms. 
     
     
         20 . The method of producing a metal material having a lubricating film according to  claim 18 , wherein the organic acid compound (B) includes an aliphatic monocarboxylic acid having a linear alkylene group with 4 or more carbon atoms or an aliphatic dicarboxylic acid having a linear alkylene group with 4 or more carbon atoms. 
     
     
         21 . The method of producing a metal material having a lubricating film according to  claim 17 , wherein the composition for direct-current cathodic electrolysis has a pH of 3.5 to 12.5. 
     
     
         22 . The method of producing a metal material having a lubricating film according to  claim 18 , wherein the composition for direct-current cathodic electrolysis has a pH of 3.5 to 12.5. 
     
     
         23 . The method of producing a metal material having a lubricating film according to  claim 19 , wherein the composition for direct-current cathodic electrolysis has a pH of 3.5 to 12.5. 
     
     
         24 . The method of producing a metal material having a lubricating film according to  claim 20 , wherein the composition for direct-current cathodic electrolysis has a pH of 3.5 to 12.5. 
     
     
         25 . A metal material having a lubricating film comprising a metal material and a lubricating film disposed on a surface of the metal material,
 wherein the lubricating film includes:   at least one type of metal element selected from the group consisting of divalent or higher valent main group metal elements (excluding elemental zinc) and rare earth elements; and   an organic acid compound having a carboxyl group and a linear alkylene group with 4 or more carbon atoms per molecule, and/or its salt, and   wherein in a depth profiling analysis of the lubricating film by glow discharge optical emission spectrometry as conducted on the lubricating film from its surface opposite from a side facing the metal material in a direction toward the metal material, a ratio (Im/Is) between a peak intensity derived from elemental carbon at the surface of the lubricating film opposite from the side facing the metal material (Is) and a peak intensity derived from elemental carbon at a middle level in the lubricating film corresponding to a half of a whole thickness of the lubricating film from the surface opposite from the side facing the metal material (Im) is less than 1.0.   
     
     
         26 . The metal material having a lubricating film according to  claim 25 , further comprising, on the lubricating film, an oil layer containing an oil component.