TWI Frequently asked questions

What types of coating can I apply with arc spraying?

by Suman Shrestha

Arc spraying, also known as twin-wire arc spraying, is used to apply coatings of metals and metal alloys. The process is most commonly used to deposit zinc and aluminium alloys to provide corrosion protection of an underlying steel substrate. Coating quality does not usually match that achieved by plasma or HVOF spraying, but the process does allow for high deposition rates, typically up to 15kg/hr. Porosity is in the range 5-10%. Coating thickness is usually about 0.2 - 10 mm. The diameter of the electrode wire is typically in the range 2-5 mm. Bond strengths can vary between 60-85 MPa and are often higher than those achieved by flame spraying but usually not as high as those achieved by plasma or HVOF spraying.

Commonly deposited coating materials include:

• Aluminium
• Copper
• Zinc
• Nickel
• Bronzes
• Steels
• Core wires containing a harder particulate material, such as a carbide

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