الفهرس 
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Abstract
Copper composite material is presented as suitable candidate for heat sink and heat spreader due to its high thermal conductivity (TC) and low coefficient of thermal expansion (CTE). In this study copper composites reinforced with diamond particles were fabricated by a powder metallurgical method (powder mixing with subsequent pressure assisted consolidation). The effect of diamond volume fraction (V f %) in the Cu/diamond composite on the properties of the composite was studied. It is known from the experiments that there is a very weak. bonding between diamonds and pure copper matrix in the consolidated composite. In order to improve the interfacial behavior between copper and the reinforcement, diamond particles were electroless coated with NiWB or CoWB or NiCrB alloys. The coated powders were cold compacted at 100 bar then sintered at 900°C. For comparison, identical materials compositions were prepared by mixing the powders constituents mechanjcally, compacted and sintered at the same conditions. The prepared powders and sintered materials were investigated using X- ray diffraction (XRD) and scanning electron mIcroscope equipped with an energy dispersive X-ray analysis (SEM/EDS). Improvement bonding strength, mechanical, and thennal propeliies were achieved for the different composites. The results show that coated diamond particles distribute uniformly in heat sink materials (copper composite) and the interface between diamond particles and Cu matrix is clear and well bonded due to the formation of a thin layer from borides and carbide between Cu and diamond interfaces. The properties of the composites materials using coated powder, such as hardness, transverse rupture strength, thermal conductivity, and coefficient of thennal expansion (CTE) were exhibit greater values than that of the composites using uncoated diamond powder. Additionally, the results reveals that the maximum diamond incorporation could be attained at 20 V f %. The copper composites with good interfacial bonding show increase in thermal conductivity compared to pure Cu. The produced composites with coated diamond exhibit a thermal conductivity> 400 W/mK combined with 5-6 x 1O-6/K coefficient of thermal expansion (CTE).