M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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In this study, the effects of the reduction of particle size on the Y123 superconductor were investigated. The structural analysis of the samples whose particle size were reduced by using an agad mortar machine and planetary ball mills were performed by benefiting from XRD, DTA and SEM, and physical and magnetic properties of the samples were determined using the low temperature resistance and magnetization measurements. The reduction of particle size was made by means of method of mechanical alloying. This process was performed in two ways. The first, the nominal composition of Y123 powders was ground for different times. The aim of this way is to get superconductivity without heat process. The latter process is to ground for different times on Y123 superconductor produced with standard way. These two processes were carried out by using both agad mortar machine and planetary ball mills, and also the differences between these systems were investigated.It was seen from M-H curves that Y123 powders which were not subjected to any heat treatment, which were exposed to long time grinding by using agad mortar machine and planetary ball mills showed no sign of superconductivity between 20-300 K. In addition, the samples ground with agad mortar machine showed a ferromagnetic properties while the samples ground with planetary ball mills indicated a paramagnetic properties. It was found that when Y123 superconductor powders were subjected to long time grinding process through both systems, these grinding processes caused decomposition of the compound and also Y123 powders showed no sign of superconductivity after the a notable time. It was determined that the samples which were superconductors before grinding process and ground by using an agad mortar machine for a long time gained ferromagnetic properties. The samples showed no sign of superconductivity after the long time grinding were subjected to heat process to recover the pre-superconductivity properties. After this process, it was seen that superconductor transition temperature of samples decreased considerably to the low temperatures. Key words: Y123 Superconductor, Mechanical Alloying, Particle Size, Agad Mortar Machine, Planetary Ball Mills. | |||||||||||||||||||||