Mechanical behavior of ceramic capacitors

Fracture toughness, modulus of rupture (MOR), and thermal shock resistance were evaluated on COG, X7R, and Z5U type commercial ceramic capacitors with and without internal electrodes. Fracture toughness measurements show similar values for X7R and Z5U dielectrics and a slightly higher value for COG dielectrics. The presence of electrodes slightly increases the strength of all the dielectrics. MOR measurements indicate that the COG samples are relatively stronger, followed by X7R and Z5U dielectrics. Weibull modulus values are higher for X7R dielectrics followed by COG and Z5U dielectrics. These results show that the critical temperature difference for fracture initiation is close to 75°C for 5819 size samples and close to 125°C for 1206 size Z5U and 150°C for X7R and COG dielectrics