The dissertation addresses improvements in electrical joints made of thin copper wires, produced by ultrasonic welding and soldering. Due to the limited mechanical strength of thin wires in conventional ultrasonic welding, a novel ring-welding approach was developed to reduce wire deformation. The influence of welding parameters (energy, pressure, amplitude) was examined, and optimal conditions were determined for both varnished and bare wires. Despite slightly lower electrical conductivity and mechanical strength, joints made with varnished wires demonstrated higher process energy efficiency. Thermal shock testing in the range of −30 to 150 $°$C showed no significant impact on the mechanical or electrical properties of the joints. Furthermore, the study explores the use of ultrasonic welding for sealing cooling channels in Cu-ETP copper blocks as an alternative to conventional sealing methods. The developed technique enables reliable mechanical and hermetic bonding without additional materials, enhancing the durability and robustness of the joints. The final part of the dissertation focuses on corrosion protection of galvanically coupled systems composed of AA6082 aluminium alloy and Cu-ETP copper in a chloride environment. A synergistic combination of cerium acetate, sodium sulfate, and 1H-benzotriazole significantly reduces galvanic corrosion, improves passive film stability, and enhances the long-term corrosion resistance of materials under aggressive conditions.
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