Failure Analysis on T491D475K050AT Kemet Tantalum Capacitor

Gideon Analytical Laboratories received several T491D475K050AT Kemet tantalum capacitors for electronic failure analysis. A capacitor is a passive two-terminal electronic component that stores electrical energy in an electric field. While some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed to add capacitance to a circuit. The Kemet T491D475K050AT has a capacitance of 4.7 uF, a voltage rating of 50 VDC, and a tolerance of 10%, measures 7.3mm x 4.3mm x 3.1mm (LWH), has a minimum operating temperature of -55 degrees Celsius and a maximum operating temperature of 125 degrees Celsius. One of these capacitors had already been tested and found to be a dead short. The other capacitors were to be used to determine whether acid had affected the forming voltage oxide.

We conducted failure analysis on the T491D475K050AT Kemet tantalum capacitors. Sample 1 was examined; there was no external damage to the plastic or broken leads. Electrical testing confirmed a dead short. The plastic was then removed. The failure site showed fused tantalum, silver, and manganese dioxide all welling up from a cauldron looking depression. SEM-EDS analysis was then used to get reveal the elemental makeup the materials at the failure site. The SEM-EDS analysis revealed tantalum, manganese, silver, and some other elements. But there were no contaminating elements present at the failure site. We continued the SEM-EDS analysis, on different sections of the failure site but we did not find any foreign elements. We compared the failed T491D475K050AT Kemet tantalum capacitors and the good ones. We concluded that this failure was not related to contamination during the manufacturing process. The failure was an application issue caused by high voltage.

Gideon Analytical Laboratories is flexible and reasonable to do business with. We can customize analysis specifically tailored to meet the needs of our costumers. Do you need help with product design? Do you want us to target specific components on a PCB? Do you want us to X-ray a particular part? If you need specific services and consultation, we can do that too. If your products are failing, Gideon Analytical Laboratories is really the only place you need to contact. We can identify the cause of failure and help you get back on the road to success. If you need help in any way, give Gideon Analytical Laboratories a call today.

Good capacitor measuring 4.7 uF at 50V

Good capacitor measuring 4.7 uF at 50V

The capacitor after plastic was removed, E is the failure site

The capacitor after plastic was removed, E is the failure site

Spot analyzed using SEM-EDS

Spot analyzed using SEM-EDS

Micrograph of failure site

Micrograph of failure site

Micrograph of crater brim, no foreign elements present

Micrograph of crater brim, no foreign elements present

Another micrograph of failure site, no foreign elements

Another micrograph of failure site, no foreign elements

Failed capacitor, tantalum pentoxide discolored

Failed capacitor, tantalum pentoxide discolored

T491D475K050AT Kemet tantalum capacitor

T491D475K050AT Kemet tantalum capacitor

Electrically tested, dead short

Electrically tested, dead short