Skip to main content

3% Nital

General Purpose

Composition

3% Nitric Acid in Ethanol

3%

Method

Immersion

Time

10s

Alternative Names

3% Nitric AcidNital 3%

Tags

carbon-steelmedium-carbon-steelgeneral-purpose

Reveals

Grain boundaries, ferrite, pearlite, bainite

Typical Results

Similar to 2% Nital but more aggressive. Better for harder steels and bainitic structures.

Color Effects

Pearlite darkens more, ferrite remains light

Compatible Materials

medium-carbon-steelhigh-carbon-steeltool-steel

Incompatible Materials

stainless-steelaluminum

Application Method

Method:immersion
Typical Time:10 seconds

Preparation Notes

Mix 3 ml concentrated nitric acid (HNO₃) with 97 ml ethanol. Add acid to ethanol slowly with stirring.

Application Notes

Immerse sample for 10-20 seconds. More aggressive than 2% Nital. Rinse with ethanol then water.

Troubleshooting

Use for harder steels that don't respond well to 2% Nital. Reduce time if over-etching occurs.

Storage Notes

Store in dark glass bottle. Shelf life: 3-6 months.

Alternative Etchants

  • 2% Nital
  • 4% Picral

Similar Etchants

  • 2% Nital
  • 4% Nital
  • 5% Nital

ASTM References

ASTM E407