Nickel Reagent
Nickel Etchant
Material Specific
Composition
Nitric acid 20–40%, Sulfuric acid 2–10%, Sodium chloride 2–10%
PACE product, by weight
Method
Swab
Time
10–60 s
Alternative Names
Tags
Reveals
Grain boundaries; annealing twins; deformation banding in cold-worked Ni; precipitates in aged Monel K-500
Typical Results
Acid-chloride etchant (HNO3 + H2SO4 + NaCl) for commercially pure nickel (Nickel 200/201), Monel (Ni-Cu alloys 400, K-500), and other low-alloy nickel grades. The chloride breaks through the passivating Ni oxide layer; HNO3/H2SO4 develop grain structure. For higher-alloy nickel superalloys, use Inconel Etchant or Glyceregia.
Application Method
Method:Swab
Typical Time:10–60 s
Preparation Notes
PACE Nickel Etchant is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Nitric acid | 7697-37-2 | 20–40% | Yes |
| Sulfuric acid | 7664-93-9 | 2–10% | Yes |
| Sodium chloride | 7647-14-5 | 2–10% | Yes |
| Water | 7732-18-5 | 50–70% | No |
Application Notes
Swab 10–60 s at room temperature. Rinse with water then ethanol.
Troubleshooting
Aged Monel K-500 needs the longer end of the time window vs annealed Monel 400. Cold-worked Ni shows deformation bands at long dwell; that is expected.
Storage Notes
Amber glass at room temperature. Stable many months.
Alternative Etchants
- Marble's Reagent
- Inconel Etchant
Similar Etchants
- Marble's Reagent