Etchant for etching workpieces made of aluminum and aluminum alloys

Abstract

An etchant includes nitric acid (HNO 3 ) having a percentage by mass in the approximate range of 4%-6%, hydrochloric acid (HCl) having a percentage by mass in the approximate range of 1%-3%; and ferric ions (Fe 3+ ) having a concentration in the approximate range of 30-70 grams/liter (g/l). The resultant etchant is suitable for etching aluminum and its alloys. In fact, the etchant is capable of etching such a material to a depth of about 0.1 mm in about 1.8 min, when employed at a temperature in the approximate range of 38° C.-48° C. The etchant further may be recycled, for which an added oxidizer may further be employed.

1 . An etchant comprising:
 a nitric acid (HNO 3 ) having a percentage by mass in an approximate range of 4%-6%;   a hydrochloric acid (HCl) having a percentage by mass in an approximate range of 1%-3%; and   a source of ferric ions (Fe 3+ ) having a concentration in an approximate range of 30-70 grams/liter (g/l).   
     
     
         2 . The etchant as claimed in  claim 1 , wherein the percentage by mass of the nitric acid (HNO 3 ) is approximately 5%. 
     
     
         3 . The etchant as claimed in  claim 1 , wherein the percentage by mass of the hydrochloric acid (HCl) is approximately 2%. 
     
     
         4 . The etchant as claimed in  claim 1 , wherein the ferric ions (Fe 3+ ) have a concentration of approximately 50 grams/liter (g/l). 
     
     
         5 . The etchant as claimed in  claim 1 , wherein the etchant is capable of effectively etching aluminum or an alloy thereof at a temperature in an approximate range of 38° C.-48° C. 
     
     
         6 . The etchant as claimed in  claim 1 , wherein the ferric (Fe3 + ) ions are provided by a soluble ferric compound dissolved in the etchant. 
     
     
         7 . The etchant as claimed in  claim 6 , wherein the ferric compound is chosen from the group consisting of ferric chloride (FeCl 3 ), ferric bromide (FeBr 3 ), ferric iodide (FeI 3 ), and a mixture of at least two kinds of these kinds of ferric halide. 
     
     
         8 . The etchant as claimed in  claim 1 , wherein the etchant further includes an oxidizer. 
     
     
         9 . The etchant as claimed in  claim 8 , wherein the oxidizer is chosen from the group of sodium chlorate (NaClO 3 ) and potassium chlorate (KClO 3 ). 
     
     
         10 . The etchant as claimed in  claim 1 , wherein the etchant is capable of etching at least one of aluminum and an aluminum alloy to a depth of about 0.1 mm in about 1.8 min, when employed at a temperature in the approximate range of 38° C.-48° C.