Tin allows can be difficult to prepare because it is very soft and distortion to the microstucture can easily occur. If not removed this distorted layer hides the true microstructure. In addition, if any excessive heat occurs during preparation the microstructure can also be masked by surface recrystallized. Proper preparation requires minimizing damage. For tin and tin alloys, alternating between polishing and etching is often required in order to remove the damaged microstructure. The recommended etchant is 2% nital (2 ml nitric acid in 100 ml methanol or ethanol); etch for only a few seconds before repolishing.
SECTIONING
MAXCUT Abrasive blade (MAX-C or MAX-I series)
MOUNTING
Compression Mounting with Phenolic, Epoxy or Diallyl Phthalate compression mounting resins
POLISHING
Abrasive/surface |
Lubricant |
Force/ sample |
Speed |
Time |
P240 grit ALO paper |
Water |
5-10 lbs |
100/100 rpm |
Until plane |
1 um DIAMAT diamond on ATLANTIS polishing pad |
DIALUBE Purple Extender |
5-10 lbs |
100/100 rpm |
2 minutes |
0.05 um Nanometer alumina on NAPPAD polishing pad |
|
5-10 lbs |
100/100 rpm |
1 minute |
 |
Tin-Antimony-Copper (hard tin), 100X, 2% nital etchant for 2 seconds |
 |
Tin-bismuth alloy, 200x, etchant 2% Nital |