SNF (sodium naphthalene formaldehyde, short for sodium naphthalene sulfonate formaldehyde condensate) is a strong anionic dispersant. In ceramics it is tested as a deflocculant for slips and glazes, where it lowers viscosity at a given water content. Lignosulfonates are the more common low-cost ceramic additive; SNF is usually considered where stronger dispersion is needed.
Where It Is Tested in Ceramics
| Use | Role | Alternatives |
|---|---|---|
| Body and tile slips | Deflocculant: fluid slip at lower water content, so less drying | Sodium silicate, sodium polyacrylate, lignosulfonate |
| Glaze suspensions | Keeps glaze particles dispersed | Polyacrylates |
| Refractory castables | Dispersant in the matrix | Polycarboxylates, phosphates |
How to Test
- Measure slip viscosity or flow time at fixed water content across a range of additions to find the minimum (the deflocculation curve).
- Check stability over time; over-dosing can thicken the slip again.
- Check green strength and drying behaviour of the formed body.
- Compare cost-in-use against your current deflocculant.
Grades
| Grade | Sodium sulfate (Na2SO4) | Chloride (Cl–) | Cement paste fluidity | Solids | pH |
|---|---|---|---|---|---|
| SNF-5 (GAC-SNF-5) | 5% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-10 (GAC-SNF-10) | 10% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-18 (GAC-SNF-18) | 18% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| SNF-20 (GAC-SNF-20) | 20% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| Powder Grade, high solids (GAC-SNF-P) | 10% max | Below 200 ppm | Not listed | 95% min | 6.5 – 8.5 (1:10) |
Lignosulfonate options for ceramics are on lignosulfonates for ceramic processing. SNF grades and samples: SNF superplasticizer product page.
Frequently Asked Questions
What does SNF stand for?
Sodium naphthalene formaldehyde, short for sodium naphthalene sulfonate formaldehyde condensate.
Is SNF used in ceramics?
It is tested as a deflocculant for slips and glazes and as a dispersant in castables. Sodium silicate, polyacrylates and lignosulfonates are the more common choices.
How do I find the right SNF addition for a slip?
Run a deflocculation curve: measure viscosity at fixed water content across several additions and choose the minimum.
