Arc Wire Spraying
The arc spray process is based around the creation of an arc between two electrically charged metallic wires, which act as consumable electrodes, and using this arc to melt the incoming wires. Drive rolls feed the wires through the gun system to the nozzle. The contact of the wires creates the arc and melts the wire at temperatures in excess of 4000 degrees C. The molten material is atomised by the flow of compressed air through the gun and propelled towards the substrate, where the impacting particles rapidly solidify to form a coating.
The high particle velocity in arc spraying lends itself to forming a very high bond strength between the coating and the substrate, and for the production of very high spray rate coatings. Also, arc spray coatings are typically denser than their flame spray equivalents.
Another feature of this process is that it allows for the feeding of different metal wires simultaneously through each electrode to produce pseudo-alloys.
The arc wire spraying process is sometimes referred to as a ‘cold process’, because the temperature of the substrate material can be kept very low, thus avoiding any distortion or damage to the substrate. However, this also means that if substrate pre-heating is necessary, then a secondary heat source is required.
Coatings applied with arc spraying:
- Pure metals (Cu, Al, Zn, Ni, Mo, Sn)
- Alloys (NiAl, CuSn, NiCr, NICu, …….)
The vast variety of material combinations allow arc spray to be used in a wide spectrum of industrial applications providing:
- wear resistance
- oxidation, shock and abrasion resistance
- dimensional restoration
- corrosion protection
- electrical conductivity
- cosmetic repairs