Method for electrolytic surface modification of flat metal workpieces in copper-sulfate treatment liquid containing sulfate-metallates

Abstract

The invention relates to a method for the electrolytic surface modification of a flat workpiece by the deposition of copper aggregates. The invention also relates to flat metal workpieces that can be produced using this method and to the use of said metal workpieces as substrates for the formation of secure adhesive bonds comprising a plurality of materials.

1 - 13 . (canceled) 
     
     
         14 . A method for the electrolytic surface modification of a flat metal workpiece, comprising;
 (a) anodically polarizing at least one surface of the flat metal workpiece with a treatment liquid, whereby an anodic dissolving process is induced, and then   (b) cathodically polarizing said at least one surface of the flat metal workpiece with the treatment liquid, thereby inducing a cathodic deposition for the deposition of one or more metals on the at least one surface of the flat metal workpiece,
 wherein said treatment liquid is comprised of a conductive liquid based on sulphuric acid/sulphate solutions of copper and one or more members selected from the group consisting of yttrium, lanthanum and lanthanoids, wherein the ratio between (i) the sum of the amount-of-substance fractions of yttrium, lanthanum and/or the lanthanoids, where contained, and (ii) the amount-of-substance fraction of copper is at least 0.0182. 
   
     
     
         15 . The method according to  claim 14  wherein the amount-of-substance fraction of copper is 0.0182 to 0.127. 
     
     
         16 . The method according to  claim 14 , wherein the flat metal workpiece is anodically polarized by at least one cathode without direct contacting for the induction of the dissolving process, and the flat metal workpiece is cathodically polarized by at least one anode without direct contacting for the induction of the deposition process, and the cathode and the anode are arranged in such a way that treatment liquid is located between anode and metal workpiece and between cathode and metal workpiece. 
     
     
         17 . The method according to  claim 14 , wherein the concentration of the sum of yttrium, lanthanum and lanthanoids, where present, in the treatment liquid is at least 0.01 mol/l. 
     
     
         18 . The method according to  claim 17  wherein the concentration of the sum of yttrium, lanthanum and lanthanoids, where present, in the treatment liquid is in the range from 0.014 mol/l to 0.35 mol/l. 
     
     
         19 . The method according to  claim 14  wherein the treatment liquid comprises a conductive liquid based on sulphuric acid/sulphate solutions of copper and lanthanum. 
     
     
         20 . The method according to  claim 14  wherein the lanthanum is present as lanthanum oxide 
     
     
         21 . The method according to  claim 14 , wherein the treatment liquid additionally comprises an additive of the general formula (I):
   HO—CHR 8 —CHR 9 —Z—(CHR 4 —CHR 5 —Z) n —CHR 6 —CHR 7 —OH  (I)
   in which:   n=an integer from 1 to 11,   Z═S or O,   R 4 ═H, C 1-4 -alkyl or phenyl,   R 5 ═H, C 1-4 -alkyl or phenyl,   R 6 ═H, C 1-4 -alkyl or phenyl,   R 7 ═H, C 1-4 -alkyl or phenyl,   R 8 ═H, C 1-4 -alkyl or phenyl, and   R 9 ═H, C 1-4 -alkyl or phenyl.   
     
     
         22 . The method according to  claim 21 , wherein the additive is 1,8-dihydroxy-3,6-dithiaoctane. 
     
     
         23 . The method according to  claim 14 , wherein a metal strip or a metal foil is used as flat metal workpiece. 
     
     
         24 . A flat metal workpiece upon which is deposited on the surface thereof metal aggregates in the form of balls covered with vertical lamellae, said surface having average roughness values Ra and Rz values, as determined in accordance with DIN EN ISO 4288:1998, ranging from 0.22 to 0.32 μm and 1.4 to 2.1 μm, respectively. 
     
     
         25 . The flat metal workpiece according to  claim 24 , wherein the average roughness values Ra and Rz range from 0.24 to 0.28 μm and 1.6 to 1.9 μm, respectively. 
     
     
         26 . The flat metal workpiece according to  claim 24 , wherein the metal surface has an adhesive strength, as determined by the 180° peel test using an FR-4 epoxy resin and expressed as peel strength in N/mm, of 1.5 N/mm or greater. 
     
     
         27 . The flat metal workpiece according to  claim 24  comprised of a metal consisting of copper, tin, silver and iron or a metal alloy comprised of copper, iron, silver or tin. 
     
     
         28 . The flat metal workpiece according to  claim 24  comprised of copper. 
     
     
         29 . The flat metal workpiece according to  claim 24 , where the metal balls deposited on the flat metal workpiece are comprised of copper balls. 
     
     
         30 . The flat metal workpiece according to  claim 29 , which is a copper foil or a copper strip, the surface of which having the peel strength of 1.5 to 3.0 N/mm. 
     
     
         31 . The flat metal workpiece according to  claim 27  wherein the metal aggregates located on the surface of said metal workpiece are additionally comprised of lanthanoid. 
     
     
         32 . Flat metal workpiece produced by the method according to  claim 14 . 
     
     
         33 . A composition of matter comprised of the flat metal workpiece of  claim 27 . 
     
     
         34 . A composition of matter comprised of the flat metal workpiece of  claim 32 . 
     
     
         35 . The composition of matter according to  claim 33  which comprises the flat metal workpiece bonded to a material selected from thermoplastics, synthetic resins, adhesives, lacquers and pastes. 
     
     
         36 . The composition of matter according to  claim 34  which comprises the flat metal workpiece bonded to a material selected from thermoplastics, synthetic resins, adhesives, lacquers and pastes.