How to detect whether corona is generated on the surface of a film
What is corona?
Under high voltage, ionization discharge easily occurs on the surface of the medium, resulting in corona phenomenon. Corona can cause changes in surface morphology, such as oxidation, changes in surface chemical properties, etc., which will have an impact on the film preparation process and performance.
How to detect corona
1.Visible light microscopy observation
Visible light microscopy can be used to observe whether there is corona phenomenon on the surface of the film. The surface of the corona region will be polarized, causing obvious color changes on the surface under a microscope. This method is simple and easy to implement, but it is only suitable for situations where surface corona is obvious.
2. Charge distribution test
The charging test device can measure the charge distribution on the surface of the sample to determine the location and shape of the corona. This method can quantitatively analyze the characteristics of corona with high accuracy.
3. Charge density measurement
By measuring the current on the surface of the film, the distribution of charge density at the onset of the corona can be determined. Through multiple tests, it is possible to determine the location of corona generation and provide early warning of corona.
Measures to prevent corona
1. Selection of membrane materials
Choosing materials with high dielectric constant and low dielectric loss coefficient can reduce the possibility of ionization on the film surface. The selection of membrane materials should also take factors such as transparency and production cost into consideration.
2. Control the electric field strength
Reduce the possibility of corona by controlling the electric field intensity during the production process. Controlling the electric field intensity can be achieved by changing the electrode gap, changing the voltage, etc.
3.Keep dry
Humidity can have an impact on corona. Maintaining a dry state in the production environment can reduce the negative effects of water vapor. In addition, ensure that the surface is dry before sample processing.
In short, the generation of corona has adverse effects on film preparation. Through laboratory testing and controlling the electric field strength, the generation of corona can be effectively prevented. At the same time, the selection of membrane materials and keeping them dry are also important measures to prevent corona.
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