10% Oxalic Acid (Electrolytic)

Electrolytic

Composition

10g (COOH)₂·2H₂O, 100ml H₂O

10%

Method

Electrolytic

Time

1.5 min at 6 V DC

Alternative Names

Reveals

Step / dual / ditch boundary structure per ASTM A262 Practice A; sigma phase; chi phase; carbides

Typical Results

The chromium-carbide sensitization screen for austenitic and duplex stainless steels (ASTM A262 Practice A). Step structure indicates an unsensitized matrix, dual structure is transitional, and ditch structure means continuous intergranular attack (sensitized, susceptible to IGSCC).

Application Method

Method:Electrolytic

Typical Time:1.5 min at 6 V DC

Preparation Notes

Dissolve 10g oxalic acid dihydrate in 100ml distilled water. Use as electrolyte in electrolytic etching setup.

Application Notes

Sample is the anode; stainless cathode. Apply 6 V DC at roughly 1 A/cm² for 1.5 min per A262 Practice A. Rinse with water, then ethanol; air-dry.

Troubleshooting

Interpret morphology against the A262 reference micrographs. Under-developed boundaries: extend time. Pitting attack: reduce time or current density.

Storage Notes

Glass bottle at room temperature. Stable many months.

Alternative Etchants

Glyceregia
Murakami's Reagent (boiling)
Chromic Acid (Electrolytic)

Similar Etchants

Chromic Acid (Electrolytic)