The Influence Of Phase Formation And Microstructure Of Y₃Ba₅Bu₈O_y Superconductor In Different Sintering Condition

According to the different proportions of atoms, in the family of YBCO high temperature superconductor, research teams have found many YBCO superconductors of different phases, such as Y-124 phase ? Y-247 phase ? Y-248 phase. But because the transition temperature of these superconducting is lower than the transition temperature of YBa2Cu3O7-x, so their research concluded without concrete result. However, many research teams still want to explore superconductors higher than YBa2Cu3O7-x by study the regulation of phase and its structure characteristics. In 2009, one of Iran's research team found the superconductors named Y3Ba5Cu8 Oy,then, there came more and more different researches about Y3Ba5Cu8 Oy. This article also tried to preliminarily explore to the Y3Ba5Cu8 Oy, it mainly focus on the formation process and the change of microstructure of Y3Ba5Cu8 Oy phase, and then by comparing with those of the YBa2Cu3O7-x, a series of results are obtained.First of all, we successfully preparation the superconducting powder named Y3Ba5Cu8 Oy using the citrate-nitrate auto-combustion reaction, through XRD test analysis,sintering temperature plays a vital role in the process of Y3Ba5Cu8 Oy superconductor phase formation, it also shows that the best temperature for phase Y3Ba5Cu8 Oy formation is 880 ?.Second, We found that the lattice parameter of the Y3Ba5Cu8 Oy is almost the same with that of YBa2Cu3O7-x by analyzing its lattice parameter, and its lattice parameter a,b is also similar to the YBa2Cu3O7-x lattice parameter a and b. But the only difference is that the lattice parameter of Y3Ba5Cu8 Oy in c axis is three times that of the YBa2Cu3O7-x. After our analysis, we found that c axis is relevant to the number of layers of Cu-O in the YBCO superconductor.Through the SEM test analysis, the influence of different sintering temperature on the morphology can not be ignored. When the temperature increased, the particle size of samples changes correspondingly, with the increase of grain size, the pore gradually reduce, which leads to the enhancement the sample surface density, and as a result, the physical properties and mechanical properties of the superconductor has been certainly promoted.Finally, through TEM test and analysis, we found that at the same sintering temperature, sintering time on the morphology of samples effect is not very big, although we can see the particles grew up in the process of adding sintering time, but in fact this kind of grew up is a phenomenon of sintering kinetics called the secondary crystallization.