الفهرس 
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Abstract
Powders of Ni and Cu were produced by water atomization technique to fabricate metal matrix composites contains various percentages of (cBN) powders 1, 2, 3, 4, 5 wt.% cBN in a matrix consists of 20 wt.%Ni and 80 wt.%Cu. The prepared mixtures were cold compacted under 400 MPa, and sintered for 1000oC at 2h under controlled atmosphere of 3:2 N2/H2 gas mixture. The chemical composition of the prepared powders as well as the microstructure composites were investigated by X-ray diffraction as well as field emission scanning electron microscope (FESEM) equipped with an energy dispersive spectrometer (EDS). The results observed that the produced Cu and Ni powders have spheroid shape but the investigated cBN has a flake like shape with sharp edges. Sieve analysis of the amount of copper powder is 100 gm and that of nickel is 10 gm. Only fine particles are used here, and the largest particle size of copper is less than 53µm, while nickel powder shows different sizes between 125µm to 53µm size less than 125 micron, and the particle size of cBN about 500 nm. It has been also observed that cBN and Ni particles were homogeneously distributed in the Cu matrix of the cBN/Ni-Cu sintered composites. The density, electrical resistivity, saturation magnetization, thermal conductivity and hardness of the composites were measured. It was observed that, by increasing cBN wt.%, the relative density and thermal conductivity were decreased, while the saturation magnetization, electrical resistivity and hardness were increased.