Etching agent and replenishing liquid

Abstract

Disclosed is an etching agent for steel. The etching agent is an acidic aqueous solution including ferrous ions, ferric ions, and an acetylene group-containing water-soluble compound. The concentration of ferrous ion A % by weight and the concentration of ferric ion B % by weight in the etching agent is preferably from 0.1 to 2.5. Also disclosed is a replenishing liquid that is added to the etching agent when the etching agent is continuously or repeatedly used. The replenishing liquid is an aqueous solution including an acetylene group-containing water-soluble compound.

1 . A microetching agent for steel, wherein
 the etching agent is an acidic aqueous solution containing: ferrous ion; ferric ion; and an acetylene group-containing water-soluble compound,   a ferrous ion concentration of A % by weight and a ferric ion concentration of B % by weight satisfies a ratio A/B being from 0.1 to 2.5.   
     
     
         2 . The microetching agent according to  claim 1 , wherein the acetylene group-containing water-soluble compound is a chemical compound including an acetylene group and a hydroxy group. 
     
     
         3 . The microetching agent according to  claim 1 , wherein
 the ferric ion concentration is from 0.2 to 20% by weight, and   a concentration of the acetylene group-containing water-soluble compound is from 0.01 to 5% by weight.   
     
     
         4 . The microetching agent according to  claim 1 , wherein an acid concentration as a resulting hydrogen ion concentration in the etching agent is from 0.02 to 1.3% by weight. 
     
     
         5 . The microetching agent according to  claim 1 , wherein the ferrous ion concentration is from 0.02 to 5% by weight. 
     
     
         6 . A replenishing solution that is to be added to the microetching agent according to  claim 1  for continuous or repeated use of the microetching agent, wherein the replenishing solution contains an acetylene group-containing water-soluble compound. 
     
     
         7 . The replenishing solution according to  claim 6 , wherein the replenishing solution is an acidic aqueous solution.