Application of a pulsed atmospheric arc plasma jet for low‐density polyethylene coating

The development of a method for deposition of low‐density polyethylene (LDPE) on rotating three‐dimensional aluminum alloy substrates is presented. LDPE powder with an average diameter of 50 μm is dispersed with nitrogen as a carrier gas. This suspension is injected into a plasma plume generated by a pulsed atmospheric arc plasma jet (PAA‐PJ). The optimized PAA‐PJ operating parameters are a pulse frequency of 63 kHz, a power of 1,500 W, a plasma gas (mixture of nitrogen with 3.3% hydrogen) flow of 54 SLM (standard litre per minute), a carrier gas flow of 9 SLM, and a powder rate of up to 5 g/min. The plasma head is moved at 200 mm/s, and the substrate is rotated at 10 rev/min. The net deposition rate reaches 2.5 g/min. A homogeneous, high‐quality film with 1‐mm thickness is deposited on an approximately 100 cm2 substrate surface. A process development for the high rate deposition of a low‐density polyethylene (LDPE) on a three‐dimensional metal substrate surface is presented. The LDPE powder with a mean diameter of 50 µm is introduced into the plasma plume of a pulsed arc atmospheric pressure plasma jet, where it melts and is accelerated in the direction of the substrate. The compromise between overheating the LDPE and not sufficient melting of the powder is reached by adaption of the nozzle distance and speed to the thickness and heat conduction of the growing film.