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questions :Polaribility what is?
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[Member (365WT)]answers [Chinese ]Time :2019-03-19
When analyzing the propagation characteristics of electromagnetic waves in an infinitely uniform medium, the problem of orientation of the field vector is not prominent. The concept of polarization of waves is not important, but when there is a boundary condition (for example, there is an interface between air and earth). , the interface between the medium and the conductor, etc.), then the orientation of E (or H) is very important. On the same boundary surface, waves with different polarizations or waves with different polarization directions will produce completely different results. In addition, when analyzing the reflection and refraction phenomena of waves at different media interfaces, the waves of arbitrary polarization are always decomposed into superpositions of waves polarized in a specific direction to facilitate processing.
Polarization is caused by the movement of current and eventually causes the potential to deviate from the open circuit potential of the electrode. When the current keeps moving, both the cathode and the anode will have polarization. Polarization reduces the potential difference between the anode and the cathode, thereby reducing Corrosion current and corrosion rate. At the beginning, there are a large number of reactants around the cathode, which can reduce the electrons on the cathode in time. However, as the cathode reaction increases, the reactants around the cathode become less and less, and the products deposited after the reaction. More and more; because the reaction product can not be removed quickly, hindering the new reactants from approaching the cathode. The end result is that the excess electrons in the cathode region are not digested and more and more.With the continuous increase of electrons, the cathode potential will gradually decrease. Cathodic protection is to use this principle to reduce the potential of each point on the metal surface to the same potential value, thus reducing the potential difference between the metal surface points. To achieve the purpose of slowing down corrosion. On the contrary, if there are many reactants in the cathode region or the reaction products are easily removed, such as in flowing water, it is necessary to reduce the potential to a certain position. The electrons, that is, the polarization is difficult. For example, there are a large number of oxygen molecules around the cathode, and the cathode is difficult to polarize to the required potential. A substance capable of consuming cathode electrons is called a depolarizer..The depolarizing agent includes: 1. dissolved oxygen; 2. microbial activity; 3. water flow. When the equilibrium between polarization and depolarization is reached, the potential difference and the corrosion current between the anode and the cathode are stabilized. The corrosion rate depends on This final current...
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