8% Nitric AcidNital 8%
8% Nital
General Purpose
Composition
8% Nitric Acid in Ethanol
8%
Method
Immersion
Time
2–10 s
Alternative Names
Tags
Reveals
Prior austenite grain boundaries and tempered martensite contrast in heavily alloyed Q&T steels
Typical Results
High-concentration nital. Rare in modern practice; most metallographers prefer 5% Nital with a longer dwell. Reserved for very heavily alloyed quench-and-tempered steels where lower concentrations under-etch the prior austenite grain network.
Application Method
Method:Immersion
Typical Time:2–10 s
Preparation Notes
Mix 8 ml concentrated nitric acid with 92 ml ethanol. Add acid slowly to ethanol.
Application Notes
Immerse 2–10 s at room temperature. Very aggressive; start with the shortest time and add seconds as needed. Rinse with ethanol then water.
Troubleshooting
If 5% already over-etches, 8% will worsen it. The issue is dwell time, not concentration. Use 5% and pull faster.
Storage Notes
Tightly capped amber glass. Stable 3–6 months.
Alternative Etchants
- 5% Nital
- Vilella's Reagent
Similar Etchants
- 5% Nital