The most common etchants for copper alloys contain either ammonium hydroxide, nitric acid or ferric chloride, however, there are hundreds of more specific etchants. A good resouce for additional etchants can be found with the etchant database provided by PACE Technologies, http://www.metallographic.com/Consumables/Etch.htm
Sample Preparation: Copper alloys must be properly prepared to reveal the true metallographic microstructure. A number of recommended procedures can be found at the following links:
http://www.metallographic.com/Procedures/Copper%20Description.htm
http://www.metallographic.com/Brochures/Met-Manual-2b.pdf
CAUTION: Safety is very important when etching. Be sure to wear the appropriate protective clothing and observe all WARNINGS on chemical manufacturers SDS (Safety Data Sheets). Also review COMMENTS Section for each etchant.
| Etchant | Conc. | Conditions | Comments |
| Distilled water Ammonium hydroxide Hydrogen peroxide (3%) |
25 ml 25 ml 5-25 ml |
Seconds to minutes (use only fresh) | -Grain boundaries use less H2O2 -Grain contrast use more H2O2 |
| Distilled water Nitric acid |
50 ml 50 ml |
Seconds to minutes | Copper and copper alloys |
| Distilled water or Ethanol Hydrochloric acid Ferric chloride |
100-120 ml 25-50 ml 5-10 grams |
Seconds to minutes | Produce grain contrast |