Chromic Acid ElectrolyticElectrolytic Chromic
Chromic Acid (Electrolytic)
Electrolytic
Composition
10g CrO₃, 100ml H₂O
10%
Method
Electrolytic
Time
30–120 s at 6 V DC
Alternative Names
Tags
Reveals
Grain boundaries; Cr-rich carbides at sensitized boundaries; sigma phase
Typical Results
Electrolytic chromic acid (10% CrO3) for stainless steels. Alternative to 10% oxalic for sensitization screening; gentler attack and better for sigma-phase identification. CARCINOGENIC (hexavalent chromium); use only with full containment.
Application Method
Method:Electrolytic
Typical Time:30–120 s at 6 V DC
Preparation Notes
CAUTION: Chromic acid is highly toxic and carcinogenic. Dissolve 10g CrO₃ in 100ml distilled water. Use in fume hood with proper PPE.
Application Notes
Sample anode; stainless cathode. Apply 6 V DC at 0.1–1 A/cm² for 30–120 s. Rinse with water and ethanol.
Troubleshooting
Cr(VI) is a known human carcinogen; fume hood and full PPE are mandatory. Dispose of solution and rinsate as regulated waste.
Storage Notes
Glass bottle with tight cap; secondary containment. Stable many months. Hazardous-waste protocol on disposal.
Alternative Etchants
- 10% Oxalic Acid (Electrolytic)
- Murakami's Reagent (boiling)
- ASTM No. 97
Similar Etchants
- 10% Oxalic Acid (Electrolytic)