Continuation . . .

Tests carried out with ceramic X7R 1812 0.47µF /63VDC - X7R 2220 1,0µF / 63VDC after only a short storing period of t = 24 h after reflow-soldering, constantly resulted in the formation of cracks even when the bending was only 2mm to 4mm.

In tests where, in addition, the components had previously been pre-aged by means of storing at high temperatures T=100°C or with rapid change of temperatures T=-40°C / +100°C, crack formation increased. Cracks even occurred, when bending was started, at 1 mm.

As the following photos show, cracks occur in the area of the end-contacts of the capacitors due to the greater forces concentrated there. However, these cracks are not in the end contacts of the capacitors, but clearly across the ceramic material.

High Mechanical Strength of SMD Film Capacitors

The same tests were carried out with encapsulated SMD film capacitors. Apart from the basic differences in the capacitor technology, completely different concepts are realized with regard to the design of the terminating contacts.

With ceramic capacitors the end contacts are generally made of galvanized layers directly applied on the end surfaces of the ceramic bodies. These end contacts are directly used as solder surfaces.