Fuel (Liquid or Gas) and Compressed Air Flame
Via the Flame
The HVAF metal spray process is characterized by a low combustion temperature (1,960-2,010°C | 3,560-3,650°F), high particle velocities (800 to over 1,000 m/s | 2,625-3,281 ft./sec.), resulting in low-oxidized, ductile, non-porous, high-bond carbide and metal coatings. With a spray rate up to 550 g/min (73 lbs./hr), it makes the process much faster, providing a significant advantage over HVOF.
Kermetico HVAF equipment uses the energy of gas combustion in air to spray powders. The combustion temperature in a HVAF gun is typically 1,000°C (1,830°F) lower than that in a HVOF coating system.
The Adiabatic Combustion Temperature of Fuels in Oxygen and Air (a=1, 20°C, 1 Bar)
This lower temperature is ideal for the gradual heating of the feedstock particles of metals and cemented carbides to or slightly above the metal’s melting temperature. The initial oxygen content in the combustion gas mixture is 5-fold lower in our HVAF process compared to any HVOF coating process. Both factors prevent the oxidation of metals and the decomposition of carbides.