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High Velocity Oxygen Fuel (HVOF)

High Velocity Oxygen Fuel (HVOF) is a thermal spray system utilising the combustion of gases, such as Hydrogen. Fuel and oxygen mix and atomise within the combustion area under conditions that monitor the correct combustion mode and pressure.

The process creates a very high velocity which is used to propel the particles at near supersonic speeds before impact onto the substrate. One of the basic rules of spraying is that high combustion pressure = high gas velocity, high particle velocity and resulting high coating quality.

One of the key benefits of this system's high velocity is the extremely high coating density and low oxide content. The low oxides are due partly to the speed of the particles spending less time within the heat source and partly due to the lower flame temperature (around 3,000 °C) of the heat source compared with alternative processes.

HVOF Spray

The 50 Series: HV-50 HVOF System

The HV-50 HVOF System was designed with the philosophy of being reliable, functional and affordable. The HV-50 can be equipped with virtually all available HVOF processes and guns.

The HV-50 is equipped with a large amount of safety features to ensure coating operations are conducted with maximum safety. These safety features include measures such as: gas sensors, parameter safeguarding, high quality non-return valves, smart software design, auto ignition, automatic powder valve (if applicable).



Hydraulic piston rods are utilized in a broad variety of industrial areas such as civil, industrial and offshore. A hydraulic cylinder is a mechanical moving mechanism that gives a force through a stroke. Smooth and hard surfaces are required on the outer diameter of the piston rod for proper sealing. Typically piston rods are hard chrome-plated, but in the production of hard chromium plating hexavalent chromium oxide is produced. Hex chrome is a well known carcinogen. Thermal spray offers several alternative super alloy, ceramic or carbide based coatings as replacement for hard chrome plating. Thermal sprayed surfaces resist aggressive environmental conditions such as wear and corrosion. Many thermal sprayed coatings outperform the hard chrome plated coating.

Flame Wire Spraying

This is a useful process for applying relatively inexpensive coatings that typically contain high levels of oxides and porosity together with the option of achieving a rough surface finish. The process relies on the chemical reaction between oxygen and a fuel of combustion to produce a heat source. This heat source creates a gas stream with a temperature in excess of 3,000°C with correctly balanced conditions between oxygen and acetylene.

The feed stock material to be sprayed is fed into the flame in the form of a wire and compressed air is then used to atomise the molten metal and accelerate the particles onto the substrate.

Among others, the process is typically used for applying bond coat materials or materials for corrosion resistance applications.

Flame Wire Spraying

Flame Wire System Gun

Arc Wire Spraying

This form of thermal spraying uses wire material as a feed stock. An electric arc is used to provide the heat source by utilising two current carrying wires. As the wires are fed towards each other the electric current short circuits between the wires creating a temperature of around 4,000°C. This temperature causes the tips of the wire to melt and once molten, compressed air or inert gas is used to atomise and accelerate the feed metal towards the substrate.

One of the advantages of this system is that two different wires can be used simultaneously to produce a pseudo alloy. Cored wires are also available producing coatings with unique properties.

The process is often used when applying to large areas such as corrosion resistance on large components or for the building up of worn components.

Arc Wire Spraying

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Hydroil Pty Ltd
64 Audley Street, Woodville North
South Australia 5012, Australia
Phone: +61 8 8243 0066
Fax: +61 8 8244 2666
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