THERMAL SPRAYING SYSTEMS

Thermal Spraying produces high performance surfaces with a mechanical bond. There is absolutely no risk of distortion or metallurgical changes to the component.

HP HVOF

The High Pressure High Velocity Oxy-Fuel process sprays the molten droplets of coating material at extremely high velocities, resulting in surfaces of the highest possible quality and performance.

HP HVOF coatings are very dense, very well bonded, and free of the oxides and tensile stresses typically found in coatings provided by other thermal spray processes. Consequently, they perform better in service.

HP HVOF wear resistant surfaces typically provide more than 4 times the wear resistance of chrome plating, through-hardening and other hard facing techniques. They are being used around the world as more environmentally friendly and superior performing alternatives to chrome.

Surfaces combining resistance to corrosion and wear are also applied by HP HVOF.

Typical HP HVOF materials include Tungsten Carbide, Chrome Carbide, Nickel alloys such as Inconel, Cobalt alloys such as Stellite, and various carbon and stainless steels.

Electric-Arc Spraying

Electric-Arc Spray was invented in the early 20th century. Electric-arc spray uses a simple, low power arc drawn between two electrically charged wires. Arc spray equipment resembles GMAW (MIG) welding equipment, in the power source and wire feeding units. Common arc spray units are capable of spraying iron and copper alloys at rates up to 18 Kg/hr using only 12 kW (42 MJ) of electricity. Electric-arc spraying produces the fastest coating rates of any technology. Electric-arc spray devices are thermally efficient and, because there is no flame or plasma, little heat is transferred to the part being coated. This process is most suited to applications requiring relatively large build-ups, where absolute coating quality (density, oxide content etc) is not as important as coating cost and rate of deposition.

Plasma-Arc Spraying

Plasma-arc spraying is a very versatile process, spraying all materials that are considered sprayable. In plasma spray devices, an arc is formed in between two electrodes in a plasma forming gas, which usually consists of either argon/hydrogen or argon/helium. As the plasma gas is heated by the arc, it expands and is accelerated through a shaped nozzle, creating velocities up to MACH 2. Temperatures in the arc zone approach 36,000°F (20,000°K). Temperatures in the plasma jet are still 18,000°F (10,000°K) several centimeters form the exit of the nozzle.

Other Thermal Spraying Systems

For economical dimensional restoration, Arc Wire and Combustion metal spraying systems are used. Typical materials include stainless and carbon steels, nickel alloys, bronzes, aluminium, copper etc.