Plating of MgB2 thin films from molten salts via electrochemi̇cal tecnique

The discovery of MgB2 which has the highest transition temperature (39 K) among the intermetallic compounds increased the interest for science and technological applications. There are several methods developed to produce MgB2 superconducting thin films. The main subject of this study fabricated MgB2 superconducting thin films from molten salts via electrochemical synthesis that is one of this production methods. In this thesis, purposed to coat electrochemical synthesis of superconductive MgB2 thin films from molten salts on 316 austenitic stainless steel and copper. In the first part of this study, experiments were carried out in an atmosphere controlled tubuler furnace containing respectively molar ratio 10:2:5:5 for MgCl2-MgB4O7-NaCl-KCl and respectively molar ratio 3:5:5 for B2O3-KCl-MgCl2 in a graphite crucible as an anode and 316 austenitic stainless steel and copper as a cathode was used. In this first group experiments, current density, time and temperature parameters were optimized; micro structure, micro hardness, SEM photographs and EDS analysis were investigated. In the second part of this work, experiments were carried out in induction furnace containing respectively molar ratio 10:2:5:5 for MgCl2-MgB4O7-NaCl-KCl and respectively molar ratio 3:5:5 for B2O3-KCl-MgCl2 in a graphite crucible as an anode and 316 austenitic stainless steel as a cathode was used. In this first group experiments, current density, time and temperature parameters were optimized; micro structure, micro hardness, SEM photographs and EDS analysis were investigated. In experiments performed on different electrolysis time, the residual salts is cleaned difficultly because of the electrolysis time is increased. Furthermore, at applied current density between 20 mA and 6 A had been affected negatively to coating MgB2 on 316 austenitic stainless steel. The residual salt is cleaned more difficultly with insreased of electrolysis time and current density. In experiments performed investigated temperature parameters, when melting point of salts mixture, the experiments were made among of 600-800 C at tubuler furnace and among of 650-900 C at induction furnace. Although the electrolysis occured this temperature, surface of specimens had negatively results.