3. Arc spraying between two wires

The principle of arc-spraying involves sparking an electric arc between two consumable wires, with a jet of compressed air spraying the molten metal onto the substrate (figure 16 ).

Electric arc guns are powered by DC generators, with arc voltages ranging from 25 to 40 V, and current ratings from 100 to 500 A. They comprise two parts:

• a wire drive part ;

• a molten metal melting/projection section.

Wires are packaged in spools or drums and pulled through flexible sheaths by drive wheels integrated into the gun and driven by electric motors or air turbines. In the case of very rigid wires or long distances between gun and spools (over 6...