4% Picral

General Purpose

Composition

4% Picric Acid in Ethanol

Method

Immersion

Time

10s

Alternative Names

Pearlite, cementite, grain boundaries

Excellent for revealing pearlite structure. Does not attack ferrite grain boundaries as strongly as Nital.

Pearlite darkens, ferrite remains light

Method:immersion

Typical Time:10 seconds

Mix 4 g picric acid with 100 ml ethanol. Warm slightly to dissolve. CAUTION: Picric acid is explosive when dry.

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

Keep picric acid wet at all times. Never allow to dry. Store in water-wet condition.

Store in dark bottle, keep wet. Add water if solution dries. Extremely hazardous when dry.