Aluminum foil for aluminum electrolytic capacitor electrode and method for manufacturing the same

Abstract

A fluid dispersion obtained by mixing oxide particles and water is sprayed to a raw aluminum foil from a direction opposite to a travelling direction of the raw aluminum foil while the raw aluminum foil is allowed to travel. In this way, a roll-pressed mark of the raw aluminum foil is eliminated, and thus aluminum foil for aluminum electrolytic capacitor electrode is produced. Pyramidal-shaped recesses each having an acute angle tip are present all over a surface of the aluminum foil.

1 . Aluminum foil for an aluminum electrolytic capacitor electrode, which is produced by allowing raw aluminum foil to travel, and spraying a fluid dispersion obtained by mixing oxide particles and water to the raw aluminum foil from a direction opposite to a traveling direction of the raw aluminum foil so as to eliminate a roll-pressed mark on the raw aluminum foil,
 wherein pyramidal-shaped recesses each having an acute angle tip are present all over a surface of the aluminum foil.   
     
     
         2 . The aluminum foil for an aluminum electrolytic capacitor electrode according to  claim 1 ,
 wherein an L-value of Hunter Lab color system, which is a colorimetric value of the surface of the aluminum foil, is 65 or more and 80 or less.   
     
     
         3 . The aluminum foil for an aluminum electrolytic capacitor electrode according to  claim 1 ,
 wherein a capacitance per 1 cm 2  of the aluminum foil is 4.28 μF or more.   
     
     
         4 . The aluminum foil for an aluminum electrolytic capacitor electrode according to  claim 1 ,
 wherein the recess is formed in a part at a depth of up to 15 μF from the surface of the aluminum foil.   
     
     
         5 . A method for manufacturing aluminum foil for an aluminum electrolytic capacitor, the method comprising:
 winding off raw aluminum foil having a roll-pressed mark; and   allowing the raw aluminum foil to travel, and spraying a fluid dispersion obtained by mixing oxide particles and water to the raw aluminum foil from a direction opposite to a traveling direction of the raw aluminum foil so as to eliminate the roll-pressed mark on the raw aluminum foil and to form pyramidal-shaped recesses, each having an acute angle tip, all over a surface of the raw aluminum foil.   
     
     
         6 . The method according to  claim 5 ,
 wherein each of the oxide particles has a polyhedral shape having an acute angle.   
     
     
         7 . The method according to  claim 6 ,
 wherein the fluid dispersion obtained by mixing oxide particles and water is obliquely sprayed to the surface of the raw aluminum foil.   
     
     
         8 . The method according to  claim 5 ,
 wherein the recess is formed in a part at a depth of up to 15 μF from the surface of the aluminum foil.   
     
     
         9 . The method according to  claim 5 ,
 wherein a tensile force is applied to the raw aluminum foil while allowing the raw aluminum foil to travel.   
     
     
         10 . The method according to  claim 5 ,
 wherein the raw aluminum foil is allowed to travel along a travelling roller, and   the fluid dispersion obtained by mixing the oxide particles and water is sprayed to a portion immediately below from an upstream side of traveling with respect to a vertical center line of the travelling roller.   
     
     
         11 . The method according to  claim 5 , wherein a colorimetric value of the surface of the aluminum foil is enhanced as compared with a colorimetric value of the surface of the raw aluminum foil. 
     
     
         12 . The method for according to  claim 5 , wherein a hardness of the surface of the aluminum foil is enhanced as compared with a hardness of a surface of the raw aluminum foil. 
     
     
         13 . The method according to  claim 5 , wherein a capacitance of the aluminum foil is made to be 1.19 times or more as a capacitance of the raw aluminum foil. 
     
     
         14 . A method for manufacturing electrode foil for an aluminum electrolytic capacitor, the method comprising:
 winding off raw aluminum foil having a roll-pressed mark;   allowing the raw aluminum foil to travel, and spraying a fluid dispersion obtained by mixing oxide particles and water to the raw aluminum foil from a direction opposite to a traveling direction of the raw aluminum foil so as to eliminate the roll-pressed mark on the raw aluminum foil and to form pyramidal-shaped recesses, each having an acute angle tip, all over a surface of the raw aluminum foil, thereby producing aluminum foil for an aluminum electrolytic capacitor,   carrying out direct-current etching treatment on the aluminum foil for an aluminum electrolytic capacitor, and   carrying out forming treatment after the direct-current etching treatment.