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Kroll's Reagent

Material Specific

Composition

2-3ml HF, 5ml HNO₃, 100ml H₂O

2-3%

Method

Swabbing

Time

5s

Alternative Names

Kroll's Etchant

Tags

titaniumtitanium-alloyzirconium

Reveals

Alpha-beta phases, grain boundaries

Typical Results

Standard etchant for titanium alloys. Reveals alpha and beta phases with good contrast.

Color Effects

Alpha phase light, beta phase dark

Compatible Materials

titaniumtitanium-alloyzirconium

Incompatible Materials

steelaluminum

Application Method

Method:swabbing
Typical Time:5 seconds

Preparation Notes

CAUTION: HF is extremely hazardous. Mix 2-3ml HF, 5ml HNO₃, and 100ml water in plastic container. Use fume hood and proper PPE.

Application Notes

Swab sample for 5-15 seconds. Do not immerse. Rinse immediately with copious water.

Troubleshooting

HF causes severe burns. Always use in fume hood with proper PPE. Have calcium gluconate gel available.

Storage Notes

Store in plastic container. Label clearly. Extremely hazardous - follow safety protocols.

Alternative Etchants

  • Modified Kroll's
  • Keller's Reagent

Similar Etchants

  • Modified Kroll's

ASTM References

ASTM E407