The Design Of Amorphous Grain Boundary And Properties Of Cu/SiC Composites

SiC/Cu composites have good mechanical, thermal, and electrical properties, It will be the candidate materials with integrated structural/functional properties in aerospace applications. The wetting of the interfaces of SiC with Cu and their homogeneous dispersion are remarkably effect the properties of the SiC/Cu composites. So the poor wettability of the two phase interfaces limits the application of SiC/Cu composites.In this study, composite powders were obtained by coating method. First, SiC particles were coated by a layer of amorphous glass phase, and then coated with copper powders by chemical replacement reaction method. The SiC particles and Cu can get uniform dispersion, and the interface compatibility are remarkably improved. The Densification will be achieved by suitable process design, and the electric properties can be controlled by interfacial modification and interface structure design. The compacts were obtained by hot pressing. The DTA-TG, SEM-EDS and XRD techniques were used to characterize phases and morphologies of the composite particles and composites. The electric properties can be controlled by interfacial modification and interface structure design. In this research, different types of material were used to realize different interface structure between SiC and Cu. The electric properties of SiC/Cu composites were measured, researching the impact of interface amorphous glass phase control on the high-temperature resistivity of composites.Experimental results show that:Amorphous interface was formed by4SiO2-K2O addition to serve as boundary insulation under780℃for2h. The addition of interfacial glass phase could remarkably improve interface compatibility of SiC and Cu. It was shown that the density, hardness and conductivity were changed slightly with the change of the interface component. The additive amount of interface amorphous glass phase had a great influence on performance of materials. The optimum thickness of glass phase was obtained by15%volume of SiO2. With the addition of La2O3to glass phase can significantly improve the hardness of materials. More important is can effectively improve the high temperature electrical property of materials. Interfacial space charge phenomena appear for SiC/Cu composites. Different interface structure leads to different changes in space charge behavior, including the initial temperature of interface polarization, polarization strength, temperature range, and different charge transferring mechanisms.