The High Velocity Oxygen Fuel (HVOF) process relies on an oxygen-fuel mixture consisting of oxygen along with propylene, propane, or hydrogen, to produce a high quality wear resistant coating.

Powdered coating  mixture is passed through the HVOF gun.  The fuel gasses are mixed and injected into the front portion of the gun.  The thoroughly mixed gasses are ejected from the gun nozzle and ignited externally.  The ignited gases form a circular flame configuration surrounding the powdered material as it flows though the gun.  Combustion temperatures are between 5000 and 6000 degrees F., depending on fuel gas.  The circular flame shapes the powder stream to provide uniform heating, melting, and acceleration.  Pre-selected oxygen, fuel, and air values are specified for each powder material to optimize dwell time in the flame.

The key characteristic of the HVOF process is the extremely high kinetic energy that is produced and transferred between the HVOF gun and target substrate.  Typical velocities are between 5000 and 7200 fps.  With both thermal and kinetic energy, the high velocity particles are physically embedded into the substrate to form a coating with the following attributes:

• High density
• High physical bond strength
• Low porosity
• Low thermal input to the substrate
• Essentially stress free
• Relatively thick deposits possible