This diploma thesis aims to verify the properties of lead-free solders, which are subjected to accelerated aging by thermal cycling. The theoretical part describes in detail the most used lead-free solders and their characteristics. The next section describes fluxes and their important functions in the soldering process. Intermetallic compounds are also mentioned, which significantly affect the quality and service life of the soldered joint. In the practical parts, the test motif was on two different substrates - corundum ceramics and the widely used substrate FR-4 (Glass fiber fabric saturated with epoxy resin). SAC solder was chosen as the reference solder for the experiment, followed by solder containing bismuth (Sn42 / Bi58) and lead solder (Sn62 / Pb36 / Ag2). Accelerated aging by thermal cycling was performed in the temperature range from -20 ° C to 125 ° C, followed by performing a test of the mechanical strength of the soldered joint by means of a shear test. SnBi solder shows higher mechanical strength at the beginning of testing than SAC solder and lead solder, during temperature cycles, it significantly loses its mechanical properties, this is caused by increasing oxidation of the alloy. SAC solder seems to be promising, which has an almost constant decrease in mechanical strength during all temperature cycles on both corundum and FR-4 substrates.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:433260 |
| Date | January 2020 |
| Creators | Cingel, Štefan |
| Contributors | Szendiuch, Ivan, Adámek, Martin |
| Publisher | Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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