| Description |
Quality of the commercially available MgB2 powder is verified by studying its thermal, structural and low temperature magnetic properties. Further electrophoretic deposition (EPD) of the commercially available MgB2 powder on stainless steel substrates from methanol dispersion medium is reported for the first time. Various deposition parameters such as deposition medium, quantity of powder loading, deposition potential and the time of deposition have been optimized. Films were subjected to heat treatment in flowing argon ambience and excess magnesium powder. Structural, morphological and FTIR studies of the films were carried out. The films are found to be adherent, uniform and with no traces of MgO. Films showed the superconducting transition in the range 38.5–39 K. EPD setup is modified for the deposition of MgB2 coils and studied their superconducting properties. In order to study the oxidation behavior of superconducting MgB2 powder with and without addition of Mg in the wide range of temperature in air as well as in argon atmosphere. TGA-DTA studies were used to investigate the oxidation kinetics of these powder samples. The oxidation activation energy of MgB2 powder is estimated by using the Freeman-Carroll method based on the Arrhenius relation and it is found to be in the range of 60 -81 KJ mol-1. The effects of addition of Mg in MgB2 powder and effect of gaseous atmosphere on the stability of superconducting MgB2 powder is studied and reported for the first time in the literature.
Electrophoretic deposition of MgB2 films on silver substrate, from the MgB2 powder suspended in ethanol bath is carried out for the first time at room temperature with optical transmittance measurements. The addition of iodine to bath is utilized to optimize the desired suspension stability for EPD. EPD parameters such as deposition potential, additive concentration were optimized for MgB2 film deposition. The different surface morphologies of the films were engineered as films were engineered by post heat treatments followed by quenching to room temperature. X-ray diffraction studies and scanning electron microscopy studies were utilized to observe the engineered surface morphology of the deposited films and quenched films. The microwave absorption properties of surface engineered MgB2 films were studied at room temperature in the frequency range from 1 GHz to 10 GHz to reveal their potential applications in microwave cavities. Further, the relation between surface resistance and engineered surface morphologies is discussed in detail for the first time.
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