Picral Etch, 500 mL

Picral Etch, 500 mL
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  • Item #: 112
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Price $68.85

Picral Etch is a common etchant for etching heat treated steels. It contains 4% picric acid in ethanol. This etchant is listed in ASTM standard E 407 as formula number 76 "Picral".

 

User Instructions:

  • Immerse or swab the sample for few seconds to a minute or more. 
  • Close the lid after each use to avoid alcohol evaporation. 
  • Do not let the solution crystallize or dry out completely. Inspect the content periodically and add solvent as needed. Please consult SDS for more information.
  • This product will stain skin and clothing. When rinsing the sample after etching, it is advisable to rinse in water to remove the bulk of the etchant, and then immerse the sample in a beaker of alcohol, followed by flushing the surface with alcohol from a squeeze bottle.
  • This solution is saturated with picric acid already. To further increase etching speed, ASTM standard recommends adding a few drops of wetting agent such as zephiran chloride into the solution. We also sell this pre-mixed solution here.
  • To etch steels with more than 0.5% of Cr, add 5 drops of hydrochloric acid per 100 ml of Picral on your own.
  • Discard after 1 year.

 Product Applications:

  • Reveal carbides (cementite, spheroidite), pearlite and bainite.
  • Color cementite and spheroidite light pink.
  • Attack ferrite uniformly, and won’t show the ferrite boundaries.
  • Reveal prior-austenite grain boundaries of tempered steels. Please add zephiran chloride as described above for this application.
  • Highlight globular cementites (spheroidites) of spheroidized annealed steels for shape analysis. It reveals only cementites and hides ferrite boundaries.
  • Highlight carbides in tool steel for distribution analysis.

Packaging:

  • Nalgene® Leakproof Bottle, HDPE.

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