Study of Cracks in Ceramic Chip Capacitors (CDR-05) of Two Different Makes

-Multilayer ceramic chip capacitor CDR-05 (MIL part number) is one of the most used parts in ISRO’s satellite program. Cracks evolved in ceramic chip capacitors CDR-05 (size: 1825and dielectric: X7R) of two different makesduring soldering process are studied in this paper. It has been observed that CDR-05 capacitors of one particular make (Manufacturer-A) more prone to crack during soldering on to the card than the other make (Manufacturer-B), whichdoes not showsuch phenomenon during soldering process. Experiments were designed to find out the breaking strength of CDR-05 capacitors from these two makes. Modulus of rupture (MOR) was calculated theoretically by standard equation takenfrom various literatures. Thermal stresses corresponding to different temperature gradientson these capacitors were also calculated. As a part of reverse engineering, internal construction of these capacitors was studied by Scanning Electron Microscope (SEM) and elemental analysis of materials used in these capacitors was carried out by Energy Dispersive Analysis of X-rays (EDAX) techniques. Results show that the critical temperature gradient for withstanding crack is ~100°C for capacitor makeA and ~150°C for capacitor make-B. Internal construction study of make-A capacitor showed thicker external layer dielectric than that of make-B capacitor. Material composition of make-A capacitor revealed presence of higher percentage of oxygen in external dielectric layer than internal layers. However, Oxygen percentage is uniform in both external and internal dielectric layers in make-B capacitors. Keywords-MLCC, SEM, EDAX, MOR, Breaking Strength, VickersHardness, Temperature Gradient