Investigation On Structure And Related Properties Of SiC_p/Cu Composites With Interfacial Amorphous Phase

Silicon carbide particles reinforced copper matrix composites, which combine excellent electrical conductivity, heat conduction and wear-resistant performance with the advantages of low-cost and simple process, gradually become the candidate materials with integrated structural/functional properties in automobile, electronic and aerospace applications. The interfacial compatibility of Si C ceramic and metal will be achieved by designing interfacial amorphous phase and optimizing sintering process. Effects of amorphous phase on the interface structure and interfacial responses of Si Cp/Cu composites will be explored. Effects of the interface microstructure on electrical properties and the mechanical properties will be analyzed.In this work, Sodium borosilicate glasses based on the Si O2-B2O3-Na2O(amorphous phase) ternary system was chosen as sintering additive to improve the sinterability of composite and ensure a high close interface between Si C and Cu by liquid phase sintering. Powder metallurgy and vacuum hot pressing method were used to fabricate dense Si Cp/Cu composites with amorphous grain boundary. The microstructure and phase composition of the Si Cp/Cu composites were characterized by Scanning electronic microscope(SEM), energy dispersive X-ray spectroscopy(EDS), X-Ray diffraction(XRD), and Thermo-gravimetric/Differential thermal Analyzer(TG-DTA). The effects of technical parameters and interfacial amorphous phase on the mechanical properties of Si Cp/Cu composites were studied by testing the porosity, vickers hardness, bending strength and wear test of the composites. Finally, the electric properties of Si Cp/Cu composites with amorphous phase were measured, researching the impact of amorphous phase interface control on the high-temperature resistivity of composites and analyzing the interfacial properties of materials according to the effect of space charge.A eutectic of 60 Si O2-25B2O3-15Na2O(in weight percentage) was designed to prepare amorphous phase. By a series of contrast experiments, it is shown that the best sintering system of 35 Si Cp/65Cu(vol.%) composites with 20 vol.% interface amorphous phase is 750 oC, 0.5h and 40 MPa. It was found that 35 Si Cp/65 Cu composites with amorphous phase show the minimum porosity of 0.5%, the maximum hardness of 2.04 GPa and the bending strength of 255 MPa. In addition, the increase of the amorphous phase content can significantly reduce the densification sintering temperature. It was found that 35 Si Cp/65 Cu composites with 20 vol.% amorphous phase can be sintered at 750 oC which is 200 oC lower than that of amorphous phase-free sample. When the structure and element change in the zone of bonding interface were studied, it was found that the interfacial amorphous phase can avoid harmful reaction; the result is good to gain bonding interface. And in the process of wear, local lubrication of eutectic melting improves the wearability of composites. The analysis of the electrical properties of Si Cp/Cu revealed that the existence of amorphous phase significantly change the space charge of the composite interface polarization behavior.