Fig. 7 shows a steel bicycle frame that has been given a powder-coated finish. The metal has been selected for its specific properties that make it suitable...

(a) The process of powder coating involves the following steps:

1. The metal part is cleaned and degreased to remove oils, dirt, and any existing surface contaminants that would prevent the powder from adhering [1].
2. A dry powder (thermoplastic or thermoset) is sprayed onto the surface using an electrostatic spray gun [1]. The gun gives the powder particles an electrical charge as they leave the nozzle.
3. The charged powder particles are attracted to the grounded metal part and cling evenly to the surface due to the electrostatic attraction [1]. This ensures an even, consistent layer before curing.

The coated part is then placed in an oven where the powder melts, flows together, and fuses into a smooth, hard, continuous coating as it cures.

(b) One advantage of powder coating over paint for the bicycle frame is that powder coating is more durable and resistant to chipping, scratching, and fading [1]. A bicycle frame is exposed to stone chips, scratches from bike racks, and UV light from the sun, so the tougher powder-coated finish maintains its appearance and protection for longer than conventional paint. Other valid advantages include: it produces a more even finish with no drips or runs; it is more environmentally friendly because it does not use solvents; and a thicker coating can be applied in a single pass.