Copper Passivation Solution
CU-PASS-SOL
Material Specific
Composition
CuSO₄·5H₂O + H₂SO₄ in water (acidic Cu passivation)
PACE recipe, supplied ready-to-use
Method
Immersion (post-etch passivation)
Time
5–10 s
Alternative Names
Tags
Reveals
Not an etchant. Applied after etching to stabilize the copper surface and prevent tarnishing during examination.
Typical Results
Cu-Pass-Sol = copper(II) sulfate pentahydrate in dilute sulfuric acid. Classical acidic copper-passivation chemistry: the dissolved Cu²⁺ saturates the surface and inhibits further oxidation of the freshly etched copper during microscopy and short-term storage. Not an etchant; produces no microstructure development on its own.
Application Method
Method:Immersion (post-etch passivation)
Typical Time:5–10 s
Preparation Notes
PACE Cu-Pass-Sol (part no. CU-PASS-SOL) is supplied ready-to-use. Per-batch recipe (250 mL):
| Ingredient | Amount |
|---|---|
| Copper(II) sulfate pentahydrate (CuSO₄·5H₂O) | 40.04 g |
| Sulfuric acid (H₂SO₄, concentrated) | 1.5 mL |
| Water (diluted to total volume) | 250 mL |
Application Notes
After etching and water/ethanol rinse, immerse the sample 5–10 s in Cu-Pass-Sol. Rinse briefly with ethanol; air-dry. The acidic chemistry means the sample should already be in a neutral-rinse condition before passivation (rinse off etchant first).
Troubleshooting
Sample tarnishes during examination: passivation was too brief or rinse left water on the surface; redo with a longer Cu-Pass-Sol dip and ethanol-only final rinse.
Storage Notes
Glass bottle at room temperature. Stable many months. Per PACE SDS, acidic content; handle with PPE.
Alternative Etchants
- Ethanol-only final rinse (less effective)
Similar Etchants
- Acidic copper sulfate passivation chemistry