Etching agent for aluminum or aluminum alloy

Abstract

A composition of an etching agent for aluminum or aluminum alloy and a treatment method thereof are provided. The etching agent does not contain a component not suitable for a wastewater treatment, such as boron and fluorine, and has stable etching performance even when performing an etching treatment continuously. The etching agent has excellent aging resistance providing good etching uniformity and corrosion resistance after etching. This etching agent is an etching agent for aluminum or aluminum alloy, including 50 parts by mass of an aminocarboxylic acid, 5 to 300 parts by mass of at least one selected from a hydroxycarboxylic acid, a dicarboxylic acid, a polycarboxylic acid, and salts thereof, and 10 to 800 parts by mass of at least one selected from a hydroxide, a carbonate, and a bicarbonate of an alkali metal, wherein an aqueous solution of the etching agent has a pH of 8 to 10.

What is claimed is: 
     
         1 . An etching agent for aluminum or aluminum alloy, comprising:
 A) 50 parts by mass of an aminocarboxylic acid;   B) 5 to 300 parts by mass of at least one selected from a hydroxycarboxylic acid, a dicarboxylic acid, a polycarboxylic acid, and salts thereof; and   C) 10 to 800 parts by mass of at least one selected from a hydroxide, a carbonate, and a bicarbonate of an alkali metal.   
     
     
         2 . The etching agent for aluminum or aluminum alloy according to  claim 1 , wherein the aminocarboxylic acid is an α-amino acid. 
     
     
         3 . The etching agent for aluminum or aluminum alloy according to  claim 1 , wherein the alkali metal of C) is lithium. 
     
     
         4 . The etching agent for aluminum or aluminum alloy according to  claim 1 , further comprising at least one of polyvinylamine, polyallylamine, polyethyleneimine, and derivatives thereof. 
     
     
         5 . The etching agent for aluminum or aluminum alloy according to  claim 1 , further comprising crystalline aluminum hydroxide particles. 
     
     
         6 . The etching agent for aluminum or aluminum alloy according to  claim 1 , further comprising a surfactant. 
     
     
         7 . An aqueous etching solution for aluminum or aluminum alloy, being adjusted to 0.5 to 5% by mass by dilution of the etching agent according to  claim 1  in water as a solvent, wherein
 the aqueous etching solution has a pH of 8 to 10. 
 
     
     
         8 . A method of etching aluminum or aluminum alloy, comprising contacting an aluminum or aluminum alloy with the aqueous etching solution according to  claim 7 . 
     
     
         9 . The etching agent for aluminum or aluminum alloy according to  claim 5 , wherein the aminocarboxylic acid is an α-amino acid. 
     
     
         10 . The etching agent for aluminum or aluminum alloy according to  claim 9 , further comprising a surfactant. 
     
     
         11 . The etching agent for aluminum or aluminum alloy according to  claim 10 , wherein the alkali metal of C) is lithium. 
     
     
         12 . The etching agent for aluminum or aluminum alloy according to  claim 11 , further comprising at least one of polyvinylamine, polyallylamine, polyethyleneimine, and derivatives thereof. 
     
     
         13 . An aqueous etching solution for aluminum or aluminum alloy, being adjusted to 0.5 to 5% by mass by dilution of the etching agent according to  claim 12  in water as a solvent, wherein
 the aqueous etching solution has a pH of 8 to 10. 
 
     
     
         14 . An etching agent for aluminum or aluminum alloy, comprising:
 A) a component of aminocarboxylic acid comprising an α-amino acid;   B) at least one compound selected from a hydroxycarboxylic acid, a dicarboxylic acid, a polycarboxylic acid, and salts thereof; and   C) at least one alkali metal source selected from a hydroxide, a carbonate, and a bicarbonate of an alkali metal;   wherein Component B has a mass ratio to Component A of 5:50 to 300:50 and Component C has a mass ratio to Component A of 10:50 to 800:50; and comprising crystalline aluminum hydroxide particles.   
     
     
         15 . The etching agent for aluminum or aluminum alloy according to  claim 14 , wherein the α-amino acid is selected from glycine, lysine, aspartic acid and alanine. 
     
     
         16 . The etching agent for aluminum or aluminum alloy according to  claim 15 , wherein the alkali metal of C) is lithium and/or sodium. 
     
     
         17 . The etching agent for aluminum or aluminum alloy according to  claim 16 , further comprising a surfactant selected from non-ionic, cationic and anionic surfactants. 
     
     
         18 . The etching agent for aluminum or aluminum alloy according to  claim 17 , wherein Component A) is glycine, Component B) is selected from sodium gluconate and sodium tartrate. 
     
     
         19 . The etching agent for aluminum or aluminum alloy according to  claim 17 , wherein Component A) is lysine, Component B) is selected from polyacrylic acid, lithium oxalate and lactic acid.