Precious metal coatings fail in the film when they were never finished in the tank. Silver, gold, platinum, palladium, and ruthenium powders cost too much to leave as agglomerates, specks, or a streak of unwetted metal on the wall. Conductive inks, fired electronic pastes, decorative lusters, catalytic coatings, and ceramic metallizing slips all ask the same thing of the mixer: wet every particle, break the clusters, and hold a uniform metal load from the first draw to the last.
Kady International has listed this duty for years: the KADY® will disperse precious metal coatings. The mill pumps the paste or vehicle through radial slots in a high-speed rotor and drives it into the staggered slots of a close-clearance stator, at tip speeds up to 9,000 feet per minute. Impact and attrition do the deagglomeration. Upper and lower propellers keep a dense, expensive solids load moving back into the head instead of settling under it.
Send the powder, the vehicle, and the film spec. Call 207.883.4141 or send us a RFQ. We will match the head, alloy, and batch size to the metal, not the other way around.
Why Precious Metal Dispersions Are Unforgiving
A pigment agglomerate in a house paint is a color complaint. The same agglomerate in a silver conductor is an open circuit, a thin spot, or a kiln load of scrap.
- Price per gram. Heel left in a transfer tank, metal smeared on a blade, or a premix that never fully lets down is lost inventory.
- Agglomerates. Metal powders and flakes cluster. If the cluster survives into the film, conductivity, coverage, and fired density all move.
- Flake damage. Some silver and gold grades are flakes that must be wetted and separated, not ground into dust. Energy has to be aimed at clusters, not at destroying aspect ratio.
- Vehicle range. Solvent, water, resin, glass frit, and organic binder systems do not wet the same way. A slow sweep can look mixed and still leave dry metal.
- Contamination. Iron pickup, leftover pigment, or a poorly cleaned head shows up in a fired film and in the assay.
The working requirement is a finished dispersion in as few vessels as the formula allows, with wetted parts that match the chemistry.
How the KADY Head Works the Paste
The dispersion head is a slotted rotor inside a slotted stator. Material is forced through the rotor and thrown against the stator face. That is impact and attrition, not a long stir.
- Wet-out. Vehicle is driven across the powder surface so resin and solvent reach the metal instead of coating a lump.
- Deagglomeration. Clusters break at the rotor-stator face. Auxiliary propellers above and below the head return the batch for another pass through the working zone.
- Uniform metal load. Recirculation keeps high-density solids from stratifying, so the draw-off matches the charge.
- One vessel when the formula allows. Wet-out and dispersion can finish in the same mill, which cuts transfer loss of a powder priced as metal, not as pigment.
Tip speed, rotor-stator clearance, and propeller feed are set to the paste. A conductive flake ink is not run like a fritted metallizing slip. Variable-frequency drives hold the energy where the particle spec needs it.
Prove the dispersion on your powder. Kady offers free testing. Call 207.883.4141 or start at free testing and bring the metal grade and the vehicle.
Coatings That Belong on This Mill
- Conductive inks and pastes. Silver, carbon-silver, and related conductors for printed electronics, membrane switches, and heater tracks.
- Fired electronic coatings. Precious-metal conductor and electrode pastes that carry metal powder, glass frit, and organic binder.
- Decorative and luster coatings. Gold and platinum preparations for glass, ceramic, and tile, where specks and color drift are visible.
- Catalytic coatings. Platinum, palladium, and related metals on a carrier, dispersed into a washcoat or slip before coating.
- Ceramic and glass metallizing. High-solids slips that must stay uniform while they are applied and fired.
Stainless wetted parts are standard. Special alloys are available when the vehicle, the frit, or the cleaning chemistry requires them. Jacketed vessels hold temperature on viscous resin systems. Closed or vacuum covers are an option when solvent loss or air in the film is the limit.
Keep the Metal in the Product
Dispersion quality is only half the cost. The other half is how much metal never ships.
- Shorter transfer paths, because wet-out and dispersion can share one vessel.
- A head that can be cleaned, so the last batch is not the start of the next contamination.
- Lab-to-plant correlation, so a bench metal load is the same process at scale.
- Premilling ahead of a media step when the spec still needs a polish grind. Less metal sits in a second machine.
Scale Without Changing the Mechanism
The Model L lab mill uses the same rotor-stator principle as the production line, so a wet-out result on a small precious-metal charge is not a different machine at scale. Production follows the batch and the solids.
- Lab mills for formula work and customer samples.
- Top entry mills for batch pastes and multi-product tanks.
- Bottom entry mills when viscosity, discharge, or vessel geometry calls for it.
- Continuous flow mills when powder and vehicle are metered into a running stream.
- High-speed production mills for full-scale dispersion.
- Refurbished mills, rebuilt to factory specs and shipped with a new-machine warranty, when the duty is proven and the capital budget is tight.
What to Have Ready Before You Call
- Metal and grade: powder, flake, or preparation, and any frit or binder that rides with it.
- Vehicle: solvent, water, resin, oil, or slip.
- Target metal load, viscosity, and the film or fired spec you have to hit.
- Batch size, or continuous rate, and how often the formula changes.
- Alloy and cleaning limits you already know you need.
Put the Metal Through the Head
KADY® International has designed and built high-speed rotor-stator mills in Scarborough, Maine since 1949. The mills disperse, mill, and homogenize fluid and solid systems, and they are running in more than forty countries.
Talk to sales and engineering about a precious metal coating. Call 207.883.4141, or contact Kady. Ask for a lab trial if you want the powder run before you commit to a mill.
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