Copper Etchant No. 1
Copper No. 1
Material Specific
Composition
Nitric acid 30–35%
PACE product, by weight
Method
Swab or immersion
Time
5–30 s
Alternative Names
Tags
Reveals
Grain boundaries, annealing twins, alpha–beta phases in brass; grain structure in nickel-silver and Monel
Typical Results
Dilute nitric acid (≈1:2 HNO3 to H2O), a classical aggressive copper etch. Faster than persulfate or ferric chloride; useful when higher contrast is needed or when other etchants under-etch. Also effective on nickel-silver and Monel.
Application Method
Method:Swab or immersion
Typical Time:5–30 s
Preparation Notes
PACE Copper No. 1 is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Nitric acid | 7697-37-2 | 30–35% | Yes |
| Water | 7732-18-5 | 65–70% | No |
Application Notes
Swab or short immerse 5–30 s at room temperature. Rinse promptly with water, then ethanol; passivate with Cu-Pass-Sol.
Troubleshooting
Significantly faster than persulfate; start at the shortest time and add seconds as needed. Over-etch produces uneven dark attack. Yellow-brown NOx fumes evolve during use; work in fume hood.
Storage Notes
Glass bottle at room temperature. Stable indefinitely; replace when chemistry depletes from heavy use.
Alternative Etchants
- Ammonium Persulfate
- Copper No. 2
- Ammonium Hydroxide + H2O2
Similar Etchants
- HNO3-based copper etchants