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Vilella's Reagent

Specialty

Composition

1g Picric Acid, 5ml HCl, 100ml Ethanol

Mixed

Method

Immersion

Time

10s

Alternative Names

Vilella's Etchant

Tags

tool-steelhigh-speed-steelcarbides

Reveals

Carbides, martensite, grain boundaries

Typical Results

Excellent for tool steels and high-speed steels. Reveals carbides clearly.

Color Effects

Carbides dark, matrix light

Compatible Materials

tool-steelhigh-speed-steelalloy-steel

Incompatible Materials

stainless-steelaluminum

Application Method

Method:immersion
Typical Time:10 seconds

Preparation Notes

Dissolve 1g picric acid in 5ml HCl, then add 100ml ethanol. CAUTION: Picric acid is explosive when dry.

Application Notes

Immerse sample for 10-20 seconds. Rinse with ethanol then water.

Troubleshooting

Keep picric acid wet. Never allow to dry. Use fresh solution.

Storage Notes

Store in dark bottle, keep wet. Extremely hazardous when dry.

Alternative Etchants

  • 4% Picral
  • Nital

Similar Etchants

  • 4% Picral

ASTM References

ASTM E407