Prior-Austenite Grain Boundaries Etch, 500 mL



Prior-Austenite Grain Boundaries Etch is a saturated aqueous picric acid solution featuring a wetting agent. It is primarily used to reveal prior-austenite grain boundaries of martensitic or bainitic steels. Given that most steels contain trace amounts of phosphorus as impurities, this chemical works by highlighting those phosphorus particles in the prior-austenite grain boundaries. It allows the user to connect the dots and effectively trace the boundaries. This product follows the ASTM standard E 407 formula number 81 but with a different wetting agent. We use dodecylbenzene sulfonate as the wetting agent instead of the tridecylbenzene, performance is the same.

  • Option: Adding hydrochloric acid into this mixture can improve its effectiveness for steels with more than 1% chromium.

User Instructions:

The specimens must be properly prepared for metallographic studies to a mirror-like finish before etching. Room temperature etching is most common but heating (up to 185°F/85°C) can make it more effective. Do not boil it. Immerse the sample for 1 to 60 minutes with occasional swabbing for heavier grain boundary attack. After etching, some light back-polishing with alumina slurry will remove the surface smut and improve the visibility of the grain boundaries.


Nalgene® Leakproof Bottle, HDPE.

Additional information

Weight 1.5 lbs
Dimensions 4.4 × 3.5 × 6.5 in
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