Corona Charge

Definition - What does Corona Charge mean?

Corona charging is the method used to study the storage and the electric charge transport in dielectric films. This can also be described in terms of the release of that charge, which is called corona discharge. This is a self-sustainable and non-disruptive electrical discharge, most often occurring due to high voltage.

The voltage has to be applied to asymmetric electrodes where there is a fine wire or a point and a cylinder. This is brought about by the ionization of the fluid that surrounds the electrode. The conductor is electrically energized and ionization occurs when the electric field strength around the electrode is high, to form a region that can conduct. The region has to be high and not cause electrical breakdown, or arcing.

Corrosionpedia explains Corona Charge

In the corona discharge, the section of ionization is the small confined region near the wire or point. This is the place where ions and excited molecules are produced. This initiates collisions between the charged particles and the neutral ones. The negative and the positive polarity of the corona dictate the ions to be produced. The negative corona in the air produces the CO-3 ions while the positive ones produce (H2O)nH+ ions, which dominate.

Corona discharge can be used for surface treatment due to production of neutral species that include ozone and nitrogen oxide, which improve adhesion. This can be seen in the air as a bluish glow at the pointed parts of conductors with high voltages.

Some applications of corona charging include:

  • Drag reduction over a flat surface
  • Removal of unwanted electrical charges in aircraft, helping to avoid uncontrolled electrical discharge on avionic systems
  • Helping in the manufacture of the ozone layer
  • Sensitization of pool water
  • Helping scrub particles in air conditioning systems
  • Removal of unwanted volatile organic products like chemical pesticides, chemical weapon agents and solvents from the atmosphere
  • Improving the surface tension energy and wet-ability of the polymer to help in the compatibility with printing inks or adhesives

Other applications include photocopying, air ionizers, photon production, nitrogen lasers and surface treatment for tissue culture, among other uses.

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