Modified Kroll's Reagent

Material Specific

Composition

1ml HF, 3ml HNO₃, 100ml H₂O

Method

Swab

Time

5–20 s

Alternative Names

Reveals

Alpha and beta phases in titanium; slower attack than standard Kroll's, with finer detail on widmanstatten alpha and beta-Ti microstructures

Typical Results

Diluted (modified) Kroll's for sensitive titanium microstructures: beta-titanium alloys (Ti-15-3, Ti-3Al-8V-6Cr-4Mo-4Zr), fine widmanstatten alpha morphology, and prior-beta grain boundary reveal where standard Kroll's over-etches.

Application Method

Method:Swab

Typical Time:5–20 s

Preparation Notes

CAUTION: HF is extremely hazardous. Mix 1ml HF, 3ml HNO₃, and 100ml water in plastic container. Use fume hood and proper PPE.

Application Notes

Swab 5–20 s at room temperature. Rinse copiously with water; do not immerse.

Troubleshooting

HF safety same as Kroll's: calcium gluconate gel on hand; PE container only. If still over-etching, dilute further with water.

Storage Notes

PE/PP bottle at room temperature, labeled with HF symbol. Stable many months.

Alternative Etchants

Kroll's Reagent
Ti-AP-16 (attack-polish workflow)

Similar Etchants

Kroll's Reagent