Coating material in the form of single wire, cord or powder is melted in an Oxy-fuel gas flame and molten material is atomised by compressed air and accelerates towards specially prepared substrate to form dense strongly adherent coating.
This flame spray process carried out correctly is called a "cold process" (relative to the substrate material being coated) as the substrate temperature can be kept low during processing avoiding damage, metallurgical changes and distortion to the substrate material.
Combustion Wire Spray Systems:-
The metal wire is fed concentrically into the flame, melted and atomized by the compressed air, and the molten droplets are propelled towards a prepared surface where they solidify and bond to the substrate to form a coating. By controlling the rate of feed of the wire through the flame, we can control the melt and atomization of metals with various melting points.
- Low capital investment
- Simple to operate
- Wire form is cheaper than powder
- Deposit efficiency very high
- Possibly still best for applying pure molybdenum coatings for wear resistance.
- Portable system
- Preheating facility built in, unlike arc spraying
- Possible to use system in areas without electricity supply
- Limited to spraying materials supplied in wire or rod form
- Not capable of the low oxide, high density and high strength coatings of plasma and HVOF