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  • Author: Marcela Pekarčíková x
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Structural Characterization of (Re)Bco Layer Deposited by Pld and Mocvd Techniques

Abstract

(RE)BCO thin films prepared by PLD and MOCVD techniques were investigated to characterize structural defects - outgrowths in thin film. For this purpose SEM, EDX analysis and LSCM were used. Outgrowths are often penetrating into the thin films. Evident differences in chemical heterogeneity, outgrowth morphology and outgrowths density between PLD and MOCVD thin films were proven in this study.

Open access
Inhomogeneities in the Structure of High Temperature Superconducting Layer

Abstract

Superconducting layer in coated conductor was investigated to assess the inhomogeneities present in its structure and to get better insight into the effect of inhomogeneities on degradation of electric properties. In the investigation scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattered diffraction, and laser scanning confocal microscopy were used. The results obtained showed good correlation between the density of inhomogeneities across the tape width and the degradation of current transport properties determined by measurements of the current density

Open access
Structural Analysis of Superconductors at MTF: A Review

Abstract

The activities of the young STU MTF research team focused on the material properties of superconductors were reviewed for the first time. We performed structural analyses on multiple types of superconducting tapes in order to get deeper insight into the correlation between their structure and electromagnetic properties, both experimentally and by modelling. We also addressed the joining of tapes by lead-free solders.

Open access
The Effect of Increased Cu Content on Microstructure and Melting of Utilized Sn-0.3Ag-0.7Cu Solder

Abstract

The influence of increased Cu and Ag contents on the microstructure evolution in the utilized Sn-0.3Ag-0.7Cu (wt. %) solder was studied. The utilized solder was exploited in the wave soldering process at the temperatures of about 260 °C for several days. The samples investigation involved the differential scanning calorimetry, the scanning electron microscopy including the energy dispersive X-ray spectroscopy, and the X-ray diffraction techniques. To predict phase equilibria at various temperatures and temperature dependences of heat capacity, the Thermo-Calc software and the COST531 lead-free solder database were used. The original and the utilized solders were found to be very similar regarding the phase occurrence, but slightly differ from one another in microstructure evolution due to higher bulk contents of Cu in the latter solder. The obtained results contribute to both the better understanding of the microstructure evolution in low-silver Sn-Ag-Cu solders and the determination of compositional limits for those solders used in the wave soldering process.

Open access