Back ionization is a phenomenon that occurs when an excessive amount of electrostatic charge builds up on the surface of a part being coated. Here’s how it happens and why it can be problematic: Cause of Back Ionization - An electrostatic charge is applied to powder particles in powder coating, allowing them to adhere to a grounded metal part. - As powder builds up on the surface, the coating layer thickens, and an increased electrostatic field develops. - When this field becomes too strong, it can create localized high-intensity charges, which repel additional powder from adhering to the surface.