Synthesis and characterization of the spark plasma sintered copper-diamond composites
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The rapidly progressing miniaturization of microelectronic devices leads to a significant increase in the amount of heat generated by electronic systems. Therefore, it is important to design new materials that will be characterized by fast heat dissipation from the system and increased mechanical properties. These requirements can be fulfilled by the metal-diamond composites with the copper as a matrix which has high thermal conductivity. Copper-5vol.% diamond composites were prepared by mechanical alloying and next sintered using spark plasma sintering method (SPS). The effect of diamond particles size on the microstructure, mechanical and thermal properties were investigated in this paper. Measurements of the thermal stability of the tested materials were carried out on the basis of thermogravimetric tests Tg/DSC in a protective atmosphere in the temperature range of RT - 850°C. After the sintering process, scanning electron microscopy was used to observe the changes occurring in the material structure. The interfaces between the diamond and metal matrix play a important role for their thermal conductance performance. The obtained Cu-diamond composites were also characterized via X-ray diffraction method to identify the carbon forms and its behavior in the structure after sintering. Thermal properties such as specific heat, thermal diffusivity, thermal conductivity and linear expansion coefficient were analyzed as a function of temperature were analyzed. Based on experimental test it was confirmed thermal stability of all examined materials. It was found that the size of diamond grains affects the mechanical and thermal properties of copper-based composites.