Failure Analysis of Ceramic Capacitors

The application of ceramic capacitors has become more and more extensive, but we all know that ceramic capacitors will be damaged and will fail. There are many reasons for the failure of ceramic capacitors. This time we will divide the situation after the failure of ceramic capacitors. .

Through the microscopic morphology of the ceramic dielectric found by scanning electron microscopy, it can be seen that the appearance of the failure is not only the color changes but also the existence of cracks and incompleteness. There are some tiny holes of different sizes in the ceramic medium, which is equivalent to the reduction of the thickness of the medium, which may reduce the breakdown dielectric strength of the capacitor.

There is a ceramic medium between the inner electrodes. There are a few tiny holes of different sizes in the ceramic medium. At high temperatures, the electrodes are easily diffused and migrated into the ceramic medium. Under the action of moisture and impurity ions, these holes become The channel through which the electrode migrates causes the insulation resistance of the capacitor to drop, the leakage current to increase, and capacitor breakdown and burnout failure.

Our energy spectrum analysis of the metal electrode shows that the carbon and oxygen content of the electrode of the failed capacitor increases, indicating that the metal electrode is oxidized and a new carbon-containing compound is formed, which causes the loss tangent of the ceramic capacitor. D increases, insulation resistance increases, and capacitance drifts. The silver oxide having a semiconductor property is interposed, so that the equivalent series resistance of the inorganic dielectric capacitor is increased, the metal portion loss is increased, and the loss tangent value D of the capacitor is remarkably increased.