prof. Ing. Bc. Karel Dušek, Ph.D.

The topic covers the degradation of electrical equipment under different environmental conditions known as ageing. Electrotechnical devices or parts of devices that are susceptible to degradation processes will be analyzed during ageing processes, and subsequently, changes in specific electrical and material properties will be evaluated. Typical parts susceptible to degradation processes include, for example, batteries, conductive connections, capacitors, etc. The weak points based on the degradation (e.g. thermal, electrical, and mechanical) tests will be diagnosed, and, if necessary, a possible modification will be proposed to slow down the degradation mechanisms. The output of the work will be, among other things, a description of changes in selected properties during ageing with regard to degradation effects.

Due to the transition to lead-free solder alloys, there has been a change in the materials used in surface mount technology. This has led to a change, mainly to an increase of the soldering process temperatures. Such temperature change increases the failure rate caused by different thermal expansion coefficients. One of many aspect  that affects the occurrence of errors  in electronic assembly is the advancing miniaturization of electronic components, the development of new component packages, the implementation of new technologies, etc. Proper detection and limitation of causes of errors is very important for mass production. The topic of the thesis is the study of the issues in the surface mount technology with regard to limitation of such issues. These may include contamination problems, dendritic growth, whisker growth, cavity (voids) occurrence, crack appearance, delamination, wetting problems, and the like.

Lead-free solders that are nowadays used in electronic industry usually have higher melting temperature than lead-based solders. However, lead-free solder alloys having lower melting temperature than the eutectic SnPb solder alloy also exist. As an example, they may be based on Bismuth and may form SnBi solder alloy. Topic of this thesis will deal with the reliability study of low-melting temperature solder alloys and with the comparison of selected parameters with the parameters of commonly used lead-free SAC solder alloys.

Modern analytical techniques provide detailed insight into the chemical composition of materials and the volatile organic compounds released. The sensitivity and selectivity of these methods allow an understanding of the processes in materials during the manufacture or use of electrical equipment. There is a growing need for more advanced hyphenated methods for materials diagnostics and process analysis. A view of the substances released allows comparison of materials used in terms of their appropriate application in a given device as well as achieving better product quality and reliability. These analytical techniques are also irreplaceable for the determination of volatile organic compounds in indoor and outdoor air and the assessment of potential risks. The topic of this dissertation will focus on the use of mass spectrometry coupled with gas chromatography in electrical engineering, particularly from the perspective of advanced diagnostics of electronic products with respect to their manufacturing process and behavior during their lifetime.