Metallographic Tin Etchants
The most common etchants for tin alloys contain either ammonium hydroxide, nitric acid or ferric chloride, however, there are numerous more specific etchants. A good resouce for additional etchants can be found with the etchant database provided by PACE Technologies.
CAUTION: Safety is very important when etching. Be sure to wear the appropriate protective clothing and observe all WARNINGS on chemical manufacuters SDS (Safety Data Sheets). Also review the COMMENTS and CONDITIONS Section for each etchant.
Sample Preparation:
Tin alloys must be properly prepared to reveal the true metallographic microstructure. A number of recommended procedures can be found at the following links:
Recommended Etchants
| Etchant | Conc. | Conditions | Comments |
|---|---|---|---|
|
Ethanol or methanol or Distilled water Hydrochloric acid |
100 ml 2-5 ml |
Several minutes | Pure tin, tin-lead alloys, tin-antimony-copper alloys |
|
Nital: Ethanol Nitric acid |
100 ml 1-10 ml |
Seconds to minutes |
Do not exceed 10% nitric acid -explosive |
|
Distilled water or methanol
Hydrochloric acid Ferric chloride |
100 ml 5-25 ml 10 gm |
Seconds to minutes |
Tin-copper alloys |
 |
| Tin-copper alloy, etched with 2% Nital, Mag. 100X (DIC) |
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