The storage stability of tantalum capacitors is a very important issue in electronic equipment and assembly, and it is also one of the hotspots of the current research. Several problems in the application of tantalum capacitors were summarized and analyzed, combined with the moisture absorption characteristics of molded packaging materials and the absorption and expansion theory of the moisture, the failure mechanism in temperature shock and reflow soldering of the tantalum capacitors in the presence of moisture was interpreted. A new kind of tantalum capacitor encapsulation material and method were tried to improve itsmoisture resistance. Several rigorous tests and 85 ℃-85% RH-2000 h life test show that the material and technology plays a very important role for the improvement of the storage stability of tantalum capacitor.

Tantalum capacitor has wide operating temperature range, large specific capacitance and unique characteristics. Special self-healing characteristics, high reliability, good stability, can meet strict use requirements for cool environment work .

In recent years, with the development of high frequency, miniaturization and high power of electronic circuits, the volume efficiency of tantalum capacitors is becoming larger and larger, the thickness of packaging layer is becoming smaller and smaller, and the reliability and storage stability of capacitors become the core issues of concern in production and application. There are many factors affecting the storage stability of tantalum capacitors, among which the environmental effects, such as temperature and humidity, can not be ignored in the production and application of tantalum capacitors . In addition to fully sealed tantalum capacitors, other tantalum capacitors, especially those encapsulated by epoxy resin moulding, are greatly affected by moisture. In this paper, several problems of high frequency in the use of tantalum capacitors are summarized, and the main causes of this failure are explained in detail. Based on this, a new epoxy packaging material and process were used to package tantalum capacitors. The results of high-pressure cooking, high-temperature reflow welding and 85-85% RH life test showed that the packaging material and process had a very significant improvement on the storage stability of tantalum capacitors.

Moisture absorption is a common problem faced by non-gas-sealed electronic products, and is the most common factor leading to the failure of electronic components. Tantalum capacitors are easy to absorb water vapor in ambient air when they are stored in humid or ambient temperature environment, and diffuse into cathode electrolyte or spongy porous body through epoxy resin coating, thus destroying various performance parameters of capacitors, or causing breakdown of capacitors or failure of other modes. A new encapsulation material and process of tantalum capacitor were used to complete the encapsulation of tantalum capacitor. Typical specifications of 20 V-100 UF (F shell) and 16 V-330 UF (H shell) were selected to carry out 85-85% RH-2000 h external voltage life test and storage life test after high temperature cooking and 308 C continuous three reflux welding tests. The experimental results show that the stability and reliability of capacitors are improved obviously, regardless of the applied voltage or high temperature and humidity storage. It can be seen that this process plays an important role in improving the storage resistance and stability of tantalum capacitors.

Visit our website for more information: www.greentechee.com