Causes of pinholes in powder coating films and their solutions (1)
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The formation of pinholes in powder coating films is closely related to its unique melt-solidification process. Therefore, to study the formation mechanism of pinholes in powder coating films, the melt-solidification process of powder coatings must be clarified.
Powder coating, as its name implies, is a powdery coating. During the coating process, first, electrostatic spraying is used to adsorb or accumulate on the substrate surface in a loose structure. After the spraying is completed, the workpiece enters the hot drying tunnel, and the substrate and coating melt and flow under heat. The original loose structure or stacking mode is destroyed with the powder particles melting and flowing. It should be particularly mentioned that a local vortex effect caused by liquid flow during film formation is called a Bernard vortex.
