High-velocity oxy-fuel spraying

High-velocity oxy-fuel spraying

High-velocity oxy-fuel (HVOF) spraying is characterized by continuous internal gas combustion in the HVOF gun. The spraying material in powder form is added to the gas exiting through a de Laval nozzle. The pressure of the torch gas which is expanded using a de Laval nozzle transforms into a high velocity of the gas jet. In the process, the spraying particles are accelerated to a velocity of up to 550 m/s and partially or completely molten by the hot gas at a temperature of around 3,200 degrees Centigrade.

As the velocity of the particles is relatively high HVOF produces very dense spray coatings. The process also permits comparatively thick coatings to be deposited. It is particularly suitable for the application of wear-protection coatings.