Arc spray, also known as twin wire arc spray or electric arc wire spray, is a thermal spray coating process that involves two metallic wires and atomizing them into fine droplets that are propelled onto a surface to form a coating. The resulting coating has a dense and strong bond to the substrate, making it a popular choice for applications where wear resistance, corrosion protection, or dimensional restoration are required. Arc spray is commonly used in industries such as aerospace, automotive, and oil and gas to improve the performance and durability of components and structures.

Process description arc spray

Two metallic wires are needed for the coating feedstock. The two wires are electrically charged with opposing polarity and are fed into the arc gun at matched, controlled speeds. The tips of the two wires contact each other as they exit the spray gun. The opposing charges on the wires create enough heat to continuously melt the tips of the wires, whereby compressed air is used to atomize the now molten material and accelerate it onto the workpiece surface to form the coating.

Key benefits of this process

• Low equipment investment costs
• Excellent portability/flexibility for on-site coating jobs
• Only requires compressed air, no other process gas or cooling media
• Very High spray and application rates

Typical applications for arc spray

• Bridge decks
• Transport pipes
• Capacitors / varistors
• Welded tube seams
• Boiler walls
• Other large infrastructures
• Bond coats for other thermal spray coatings

Process basics

• Heat source: arc
• Feedstock: solid or composite metallic wires
• Arc temperature: approx. 4 000 °C (7 200 °F)
• Particle velocity: approx. 150 m/s (500 ft/s)
• Approximate application rate: 15 to 3,300 g/min 2 to 440 lb/h)