الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Copper/silicon nitride (Cu/Si3N4) composites are fabricated by powder technology process. Copper powder of particle size less than 53µm was prepared by water atomization technique and is used as metal matrix. Si3N4 powder of particle size 500-700 nm was used as reinforcement material. Homogenous (Cu/Si3N4) composite mixtures with different Si3N4 content of 2, 4, 6, 8 and10 wt.% were prepared by mixing and grinding of the constituents. The produced powder mixtures were cold pressed at 400 MPa and sintered at different temperatures of 850, 950, 1000 and 1050oC for 2hr. the cross-sectional area of the obtained sintered samples were grinded and polished for metallographic studies. The microstructure and the chemical composition of the investigated powders as well as the produced Cu/Si3N4 composites were investigated by optical, SEM and XRD. The metallographic studies of the microstructure observed that the Si3N4 particles were homogeneously distributed in the Cu matrix. The density, electrical, thermal conductivity, coefficient of thermal expansion and hardness of the produced Cu/Si3N4 composites were measured. It was observed that the relative green density, the sintered density, the electrical conductivity as well as the coefficient of thermal expansion of the sintered silicon nitride/Copper composites at 850oC, was decreased by increasing the content of the reinforcement Si3N4 phase in the copper matrix. However the hardness was increased. It is also observed that the sintered density, electrical conductivity, coefficient of thermal expansion and hardness of the Cu/Si3N4 composites were increased by increasing the sintering temperature.