synthesis and characterization of silver/alumina powders

in this research, synthesis and characterization of silver/alumina composite powders was investigated. this kind of metal/ceramic composite powders is used for fabrication of cutting tools inserts. the role of silver is toughening the final product. the powders were synthesized via co-precipitation method. the composition of the synthesized powders was ag/80% wt 〖al〗_2 o_3. silver nitrate, aluminum nitrate and sodium carbonate were used as precursors. the synthesis process had two steps: (1) precipitation of silver/aluminum compounds by adding sodium carbonate solution to the mixture of aluminum and silver nitrate solutions drop by drop and (2) calcination of the precipitates in air atmosphere. on the basis of the scanning electron microscopy (sem) investigations, the dimensions of the initial precipitates were below 2μm. furthermore, the x-ray diffraction (xrd) analysis confirmed that during calcination the initial precipitates at 800℃, the volatile constituents such as carbon dioxide evaporated completely and the desired composite compounds were formed.