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.