Corona treatment is a surface electric discharge process that enhances the adhesion of plastic or metallized films. Most plastic films (such as polyolefin films) are non-polar polymers with low surface tension. Corona treatment is used to increase the surface energy of these films, as known inks and adhesives cannot adhere firmly to their surfaces in normal conditions.

A complete corona treatment system consists of three parts: corona generator, discharge station, and transformer.

Corona treaters are increasingly used in various industries such as flexible packaging, batteries, aluminum foils, sheets, piping, cables, cups, and foaming materials. Corona treaters are especially indispensable in plastic extrusion, printing, lamination and coating processes.