NHâ‚„OH + Hâ‚‚Oâ‚‚Ammonia Peroxide
Ammonium Hydroxide + Hâ‚‚Oâ‚‚
Material Specific
Composition
50ml NHâ‚„OH, 50ml Hâ‚‚Oâ‚‚ (3%)
50:50
Method
Swab
Time
5–20 s
Alternative Names
Tags
Reveals
Grain boundaries and annealing twins in OFHC copper, brass, and bronze; alpha–beta phases in brass
Typical Results
The standard ammonia-peroxide etchant for copper alloys. Reveals grain boundaries and annealing twins cleanly. Active H2O2 is the oxidizer, so bench-mixed batches decompose within hours. PACE supplies a stabilized formulation (which is the same chemistry as ASTM No. 30).
Application Method
Method:Swab
Typical Time:5–20 s
Preparation Notes
Mix 50ml ammonium hydroxide (NHâ‚„OH) with 50ml hydrogen peroxide (3% Hâ‚‚Oâ‚‚). Prepare fresh solution - decomposes quickly.
Application Notes
Mix equal parts concentrated NH4OH and 3% H2O2 immediately before use (or use PACE pre-mixed). Swab 5–20 s. Rinse with water then ethanol; air-dry.
Troubleshooting
No etching response: H2O2 has decomposed; mix a fresh batch (or replace the bottle). Surface tarnish: passivate with Cu-Pass-Sol or rinse faster.
Storage Notes
Bench-mixed: prepare fresh each session. PACE pre-mixed: amber bottle, cool storage; replace when activity drops.
Alternative Etchants
- Ammonium Persulfate
- Copper No. 2
- ASTM No. 30
Similar Etchants
- ASTM No. 30 (same chemistry, PACE alternate SKU)