In the present work, one near‐eutectic and three hypoeutectic Sn‐Ag‐Cu alloys have been employed for soldering by induction heating. The alloys were produced by induction melting of high purity Ag, Cu, and Sn lumps. The melting behavior of the alloys was investigated by differential scanning calorimetry. The solder alloys were subsequently applied for soldering by conventional hot‐plate heating as well as induction heating and both soldering times and peak temperatures were recorded during soldering. Solder joints of two copper sheets were produced. The electrical resistance, tensile strength, and microstructure were analyzed on each soldered joint. The results indicate that the physical and mechanical properties of solder joints are determined by their chemical composition and soldering technology. Induction soldered joints not only have a slightly higher electrical resistivity but also higher mechanical strength, except of the 0.3 wt.% Ag hypoeutectic solder. The highest increase in ultimate tensile strength (28%) was observed for induction soldered joints with 1 wt.% Ag hypoeutectic solder. This effect is ascribed to the homogenous distribution of the intermetallic compounds within the eutectic in the alloy microstructure. The homogenous distribution is aided by rotation of liquid solder due to eddy currents and high‐frequency magnetic field generated during induction heating.

Sheep farmers are currently facing an oversupply of wool and a lack of willing buyers. Due to low prices, sheep wool is often either dumped, burned, or sent to landfills, which are unsustainable and environmentally unfriendly practices. One potential solution is the utilization of sheep wool fibers in polymer composites. This paper focuses on the study of mechanical vibration damping properties, sound absorption, light transmission, electrical conductivity of epoxy (EP), polyurethane (PU), and polyester (PES) resins, each filled with three different concentrations of sheep wool (i.e., 0%, 3%, and 5% by weight). It can be concluded that the sheep wool content in the polymer composites significantly influenced their physical properties. The impact of light transmission through the tested sheep wool fiber-filled polymer composites on the quality of daylight in a reference room was also mathematically simulated using Wdls 5.0 software.

High-temperature superconducting coated conductors (CC) are attractive materials for high-voltage resistive fault current limiters. Commercially produced CC tapes cannot withstand electric fields over 100 V m⁻¹, and therefore, they have to be modified by addition of thermal stabilization layer. We investigated several composite systems suitable for such thermal stabilization. As a matrix of composites, Stycast resins were used, which contain various contents of powder particles from SiC, SiO₂, PbTiO₃, ZrW₂O₈, or synthetic diamond. The thermo-physical properties such as thermal expansion, heat capacity, thermal diffusivity and direct-current electrical conductivity were measured because they are influenced by filler content in the composite. The possible highest amount of the powder can slightly increase the thermal conductivity and decrease the thermal expansion of the system to an acceptable value needed for the coating of CCs. A side effect is simultaneous drop of heat capacity; however, its value stays still high enough for the purpose of heat sinking. Overall, the best results were achieved in system with 20 vol% of SiC filler in Stycast 2850FT + Catalyst 23LV resin matrix. There the contribution of the semiconducting SiC addition to the electrical conductivity of composite was negligible.

The article presents the possibilities of diagnostics of irreversible chemical reaction ? vulcanization in case of laboratory prepared rubber mixture based on styrene ? butadiene (SBR) using measurements of selected physical parameters. Our work is focused on the measurement of current rheologic parameters (torque at defined shear deformation) and selected electrical parameters (DC conductivity) during linear increasing temperature. The individual steps of vulcanization are well identified by means of measurements of rheologic parameters, while significantly affecting the value of the electrical conductivity. The value of the electrical conductivity increases with the increasing of rate of the crossbridging reactions during vulcanization. The rate of the heating affects both types of measurements. When the rate of the heating is increasing the temperature of the beginning of networking step of reactions and also the rate of vulcanization grow. The sensitivity of the both types of measurements allows a good mathematical description of the temperature dependence of the torque and the electric conductivity during the vulcanization of rubber mixtures based on SBR.