This form of thermal spraying uses wire material as a feed stock. An electric arc is used as the heat source. As the wires are fed towards each other, an electric arc is struck between the wires creating a temperature of around 4,000°C.
This temperature causes the tips of the wire to melt and once molten state, a stream of compressed air or inert gas is used to atomise and accelerate the feed metal towards the substrate.
Characterestics of Wire Flame Spray
Material Form
Wire
Heat Source
Electric Arc
Flame Temperature (°C)
3600 to 4000
Gas Velocity (m/sec)
< 300
Porosity (%)
10 to 15
Coating Adhesion (MPa)
28 to 42
Advantages:
Coatings with good characteristics can be achieved
Two different wires can be used simultaneously to produce a pseudo alloy
Cored wires are also available producing coatings with unique properties
Applying coating to large areas is easier by this process
Used for dimensional restoration due to higher deposit efficiency
Disadvantages:
Coatings achieved are not dense and have porosity of up to 15%
Good suface preparation is very essential for good bond strength
Coatings limited to materials available in wire form with low melting tempertaure
