Annealing of aluminum wire with radio frequency discharge plasma under atmospheric pressure

Annealing of aluminum wire using radio frequency (RF) atmospheric pressure (AP) argon plasma was carried out. Experimental results demonstrated that the AP plasma could be effectively utilized in thermal treatment of the bulk of a material to change its mechanical properties. For a ϕ1 mm stranded Al wire, the elongation was increased from less than 1% to more than 20% at an RF power of 500 W and a line speed of 17.6 m/min. Effective annealing occurred in temperature range between 270 and 340 °C, and more than half of the input RF energy could be deposited on the wire as thermal energy. It is suggested that the wire was heated by both plasma gas-wire heat transfer and energy deposition due to ion sheath effect.