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Arc Spray Process
Arc spraying is the highest productivity thermal spraying
process. A DC electric arc is struck between two continuous
consumable wire electrodes which form the spray material.
Compressed gas (usually air) atomizes the molten spray material
into fine droplets and propels them towards the substrate. The
process is simple to operate and can be used either manually or
in an automated manner. It is possible to spray a wide range of
metals, alloys and metal matrix composites (MMCs) in wire form.
In addition, a limited range of cermets coatings (with tungsten
carbide) can also be sprayed in cored wire form, where the hard
ceramic phase is packed into a metal sheath as a fine powder.
The combination of high arc temperature (6000 K) and particle
velocities in excess of 100 m.sec-1 gives arc sprayed coatings
superior bond strengths and lower porosity levels when compared
with flame sprayed coatings. However, the use of compressed air
for droplet
atomization and propulsion gives rise to high coating oxide
content.
Arc Wire Sprayed 13Cr Steel Coating on Aluminum Substrate.
Coating designed to give gripping surface to rubber.
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