Analysis of the Properties of a Cu-Al_2O_3 Sintered System based on Ultra Fine and Nanocomposite Powders

摘要

In this paper synthesis of a composite based on Cu-Al_2O_3 by a thermo-chemical method is shown along with a comparative analysis of the properties of the obtained nanocomposite sintered samples, which are characterized by a good combination of electric-mechanical properties, suitable for work at elevated temperatures. Ultra fine and nanocrystal powder Cu-Al_2O_3 is obtained by a chemical method, starting from water solutions of nitrates up to achieving the requested composition with 3 and 5 percent of Al_2O_3. Synthesis of composite powders has been developed through several stages: drying by spraying, oxidation of the obtained powder of precursor and then reduction by hydrogen until the final composition of nanocomposite powder is achieved. After characterization of the obtained powders, which comprised examination by the Scanning Electronic Microscopy (SEM) method and X-ray-structure analysis (RDA), the powders were compacted with compacting pressure of 500 MPa. Sintering of the obtained samples was performed in the hydrogen atmosphere in isothermal conditions at temperatures of 800 and 900 deg C for 30, 60, 90 and 120 minutes. Characterization of the obtained Cu-Al_2O_3 of the nanocomposite sintered system comprised examination of microstructure by the Scanning Electronic Microscopy (SEM), as well as examining of electric mechanical properties. The obtained results show a homogenous distribution of dispersoides in the structure, as well as good mechanical and electric properties.