Ceramic capacitors are the most commonly used capacitors in electronic devices, with an annual production of about one megabyte. Ceramic capacitors are capacitors that use ceramics as the dielectric medium. The structure consists of two or more alternating ceramic and metal layers, which are connected to the electrodes of the capacitor.
The composition of ceramic materials determines the electrical characteristics of ceramic capacitors and their application range, which can be divided into the following three categories according to stability
Class 1 ceramic capacitors: high stability and low losses, suitable for applications in resonant circuits.
Class 2 Ceramic Capacitors: They have high volumetric efficiency but poor stability and accuracy, and are suitable for buffering, decoupling, and bypass circuits.
Class 3 Ceramic Capacitors: They are more volumetric efficient, but they are less stable and accurate.
Ceramic capacitors may fail if they are permanent, and the internal factors that lead to the failure of ceramic capacitors are as follows.
01 Voids in ceramic media
The main factors leading to voiding are organic or inorganic contamination in the ceramic powder, improper control of the sintering process, etc. The generation of voids can easily lead to leakage, which in turn leads to local heating inside the device, which further reduces the insulation performance of the ceramic dielectric and leads to an increase in leakage. This process occurs cyclically, deteriorating, and in severe cases, it leads to serious consequences such as cracking, ** and even combustion of multilayer ceramic capacitors.
02 Firing crack
Sinter cracks often originate at one end of the electrode and propagate in a vertical direction. The main reason is related to the cooling rate during the sintering process, and the cracks and hazards are similar to those of voids.
03 Delamination
The sintering of multilayer ceramic capacitors (MLCCs) is the stacking and co-firing of multilayer materials. The sintering temperature can be as high as 1000 °C. The weak interlayer bonding, the volatilization of internal pollutants during the sintering process, and the improper control of the sintering process may lead to the occurrence of delamination. The hazards of delamination and voids and cracks are similar, which are important inherent defects of multilayer ceramic capacitors.