Final answer:
In electrostatic-bed coating, dry powder is deposited on the part by spraying it with an electrostatic charge, ensuring an even coating even on complex surfaces.
Step-by-step explanation:
In electrostatic-bed coating, dry powder is deposited on a part primarily through spraying. The process employs an electrostatic charge to disperse the powder onto the surface of the object.
The powder, which is typically given a negative charge, is attracted to the positively charged parts of the object. Unlike other methods such as immersion, centrifugation, or electrophoresis, electrostatic-bed coating ensures the powder is evenly applied even in hard-to-reach areas due to the mutual repulsion of like charges and attraction of unlike charges. This technique is similar to the one used in electrostatic painting and photocopiers, where charged dry particles are attracted to specific areas to achieve a precise and even application.