SP – Equipment For High Velocity Thermal Spray Metal Gold And Silver Coatings
Key features:
- Axial powder injection
- Protection against feedstock oxidation
- No precious metal evaporation in the coating process
- Deposition of uniform, dense, high-bond gold and silver coatings 50-500 microns (0.002” – 0.020”) thick
Using The Kermetico HVAF SP System For Precious Metal Plating
HVAF equipment is well suited for a precious metal coating process due to its low combustion temperature, high technological efficiency and process stability.
The temperature of propane combustion in air – 1,980 °C (3,600 °F) is enough to preheat precious metal particles in the jet below their melting point as the dwell time is too short to melt them.
Additionally, we protect axially injected particles from overheating in the combustion chamber with inert gas.
We avoid metal deposition on the combustion chamber and nozzle walls by computational flow modeling and maximize deposition efficiency by engineering it into the trouble-free technology.
And we supply spare parts that will not wear out for hundreds of hours, providing consistent plating quality and precious metal deposition efficiency.
As a result, you will get a high-bond, 100% dense metal silver or gold coating with minimized (and predictable) material loss.
A Description Of HVAF Process For Gold And Silver Coatings
The HVAF SP Gun sprays precious metal powders, heated and accelerated by the air-fuel gas combustion products.
When entering the gun, the compressed air cools the chamber and the nozzle assembly.
The mixture of compressed air and the chosen fuel gas flows into the combustion chamber through the orifices of a catalytic ceramic insert.
The initial ignition of the mixture results in the heating of the insert above the mixtures’ auto-ignition temperature, and then the hot insert continuously ignites the mixture.
Then part of the preheated air is mixed with the fuel and combusted.
The metallic spray powder is injected axially into a wide combustion chamber.
The powder exiting the chamber is propelled into the nozzle of chosen length and configuration, where it is accelerated to a velocity that may be over 1,000 m/s.
When impacting a substrate, the spray powder particles form a coating.
Kermetico HVAF Thermal Spray Coating Equipment
Kermetico designs and manufactures three families of HVAF thermal spray equipment.
- Convertible HVOF and HVAF equipment:
Kermetico HVAF Thermal Sprayed Precious Metal Coating