What is NNO? Dispersant NNO is a sodium naphthalene sulfonate formaldehyde condensate (CAS 9084-06-4), an anionic dispersant supplied as a powder. Some plating formulators evaluate it as an additive in electroplating baths. This page explains what it may do there and how to test it.
Possible Roles in a Plating Bath
- Dispersing insoluble particles so they do not cause rough deposits.
- Acting as a carrier or auxiliary in some acid plating formulations.
- Keeping additive packages stable.
Its effect depends on the bath chemistry and the other additives. It is not a brightener by itself.
How to Evaluate It
- Run Hull cell tests with and without NNO across a range of additions.
- Check deposit appearance, throwing power and current-density range.
- Watch for foam and for any change in bath stability over time.
- Analyse for breakdown products if the bath is used for long periods.
Which Grade
For plating, grades with low impurities are usually preferred: Grade A (low sulfate) or the High-Purity grade (low free formaldehyde, naphthalene and quinoline).
| Grade | Content | Dispersing power (vs. standard) | Sodium sulfate | pH | Other limits |
|---|---|---|---|---|---|
| Grade A (GAC-NNO-A) | 95% min | 95% min | 5% max | 7 – 9 (1%) | Ca + Mg 0.4% max; insolubles 0.05% |
| Grade B (GAC-NNO-B) | 92% min | 90% min | 18% max | 7 – 9 (1%) | Ca + Mg 0.4% max; insolubles 0.05% |
| Grade C (GAC-NNO-C, HG/T 2562-2012) | Not listed | Not listed | 22% max | 7 – 9 (1%) | Water 8% max; free formaldehyde 200 ppm max |
| High-Purity (GAC-NNO-HP) | Solids 93% min | Not listed | Sulphate about 3% | 7.0 – 9.0 (2%) | Free naphthalene <5 ppm; free formaldehyde <50 ppm; quinoline <200 ppm |
Product details: Dispersant NNO product page.
Frequently Asked Questions
What is NNO?
Dispersant NNO, a sodium naphthalene sulfonate formaldehyde condensate used as an anionic dispersant (CAS 9084-06-4).
Is NNO used in electroplating?
Some formulators test it as an auxiliary or dispersing additive in plating baths. Its effect must be confirmed with Hull cell tests.
Which NNO grade suits electroplating?
Low-impurity grades: Grade A or the High-Purity grade.
