The most common etchants for brass and bronze 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: Brass and bronze 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 |
| Ammonium hydroxide (dilute solutions) |
Dilute | Immersion | Attack polishing, ASTM 30 is also a good etchant for copper and coper alloys |
| Copper No. 1 Nitric acid Distilled water |
125 ml 125 ml |
1 second to several minutes by immersion or swabbing | Common etchant for copper and copper alloys such as brass and bronze |
| Copper No. 2 Distilled water Ferric chloride Hydrochloric acid |
200 ml 10 grams 50 ml |
Immersion or swabbing | Brasses, bronzes, aluminum brass, alpha -phases in brass |