In the Arc Spray Process a pair of electrically
conductive wires are melted by means of an electric arc. The molten
material is atomised by compressed air and propelled towards the
substrate surface. The impacting molten particles on the substrate
rapidly solidify to form a coating. This arc 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.
Electric arc spray coatings are normally denser and stronger than
their equivalent combustion spray coatings. Low running costs, high
spray rates and efficiency make it a good tool for spraying large areas
and high production rates.
Disadvantages of the electric arc spray process are that only
electrically conductive wires can be sprayed and if substrate
preheating is required, a separate heating source is needed.
The main applications of the arc spray process are anti-corrosion
coatings of zinc and aluminium and machine element work on large