Microstructural Studies On The Secondary-phase NiO Particles In Bi2212 Superconductors

In this article,a high temperature superconductor of Ni-doped Bi2Sr2-xNixCaCu2O8+?(x =0.05-0.25)In this article,a high temperature superconductor of Ni-doped Bi2Sr2-xNixCaCu2O8+?(x=0.05-0.25)system were studied.we studied schematically on the phase composition of the products,crystal structure and lattice constant of the main phase,morphology,size and distribution of secondary-phase NiO particles were studied by the characteristics such as:XRD(X-ray Diffraction),SEM(Scanning Electron Microscope),TEM(Transmission Electron Microscope),EDS(Energy Dispersive Spectrometer),and so on.A further study of the orientation between NiO and Bi2212 phase,as well as the growth relationship between NiO and the impurity-phase CaO were investigated.The results showed the following five conclusion:1.There existed a large number of NiO particles,the average diameter is about 400 nanometres,and the quantity of the particles were increased with Ni-doping.2.The particles of NiO were all found to be single crystals ranged from 2 nm to 1.38 ?m.The NiO particles ranged from 100 nm to 400 nm showed a more regular morphology just like cube-spherical shape.3.There existed some orientation relationship between NiO particles and the boundary of layer-shaped Bi2212;The distribution of NiO particles located on the edges,interstices and interstratification in layered-Bi2212 crystals prepared by pelleting powder method.4.There existed more than one orientation relationship between NiO and Bi-2212,which was vertified as:(440)NiO//(460)Bi2212;[001]NiO//[001]Bi2212,The mismatch between NiO and Bi2212 is 1.49%which had been considered as full-coherent match under this contidition.5.Polycrystalline CaO could contribute to the growth of NiO particles and make them aggregation.