Electrical Corona Discharge
Electrical corona discharge is a surface treatment process that uses a high-voltage electrical field to ionize ambient air and create a low-temperature plasma near a material’s surface. This process is widely used to improve the surface energy and adhesion properties of polymers, films, foils, textiles, and other non-conductive substrates.
What Is Corona Discharge?
Corona discharge occurs when a high-voltage electrical field is applied across a small air gap, typically between an electrode and a grounded surface. The intense field ionizes the air, forming a faint, brush-like plasma (corona) that interacts with the material surface.
How It Works
- High Voltage Input: Alternating current (AC), usually between 10–30 kV, is applied to a sharp or rolled electrode.
- Ionization of Air: The electric field ionizes surrounding air molecules, creating reactive oxygen species and UV photons.
- Surface Reaction: The reactive plasma breaks molecular bonds on the surface, removes weak boundary layers, and introduces polar functional groups (e.g., –OH, –COOH), increasing surface energy.
Applications of Corona Discharge
- Printing: Improves ink adhesion on polyethylene, polypropylene, polyester films, and labels.
- Lamination and Coating: Enhances bonding between films and adhesives or coatings.
- Adhesive Bonding: Prepares plastic parts for more reliable adhesive joints.
- Packaging Industry:<
