Microscopic Studies of Internal Structure of Ag-NiO Composite Powder Prepared by Spray Pyrolysis : Preparation of Ag-NiO composite powders by spray pyrolysis (3rd Report)

The internal structure of Ag-NiO composite powders prepared by the spray pyrolysis was investigated by a microscopic analysis of the microtome section with a transmission electron microscope and a field emission scanning electron microscope. Further, the crystallite in the Ag-NiO composite powders was examined in detail by the electron beam diffraction and EDS analyses to determine the microstructure.The internal structure of the composite powders consists of Ag layer in the external region and Ag-NiO composite structure in the core region. It is guessed that the Ag layer in the external region is formed by a single crystal or a few crystallites from the results of the electron beam diffraction. In the core region of composite powders, Ag particles and NiO particles are found as crystallites of a single crystal, which are confirmed respectively by EDS and electron beam diffraction analyses. The particle size of NiO measured by TEM is about 20 nm. It is in good agreement with the crystallite diameter of NiO which is calculated from the half-power band width of X-ray diffraction