Investigation On Interfacial Glass Phase Modification And Properties Of SiC/Cu Composites

SiC/Cu composites have wide application prospects in the field of aerospace,electrical contact and electronic packaging,etc,because of good mechanical properties,thermal properties and tribological properties as well as low production cost and easy preparation.The performance improvements and applications of SiC/Cu composites are mainly limited to the poor wettability and severe interfacial reaction between two phases.So improving the wettability and controlling interface reaction between SiC and Cu are the key to improve the comprehensive properties of SiC/Cu composites.In this paper,the 50SiO₂-20B₂O₃-30Na₂O?wt.%?glass phase was introduced to improve the wettability between SiC particles and Cu matrix and control the interfacial reaction between two phases,which could further improve the properties of SiC/Cu composites.Si C/Cu composite powders were prepared by coating method and mechanical mixing method.SiC/Cu composites with different interfacial structures were prepared by vacuum hot pressing sintering technology.Interface modification was carried out by introducing graphite during the process of SiC particles coated with glass phase.The phase composition,microstructure,density,flexural strength,vickers hardness,coefficient of thermal expansion,thermal diffusivity and friction coefficient of Si C/Cu composites were characterized by XRD,SEM and other experimental methods.The influence of glass phase content on the density,mechanical properties and thermal properties of SiC/Cu composites was investigated and then the effect of the glass phase and graphite content on the tribological properties of SiC/Cu composites was studied.The research results are as follows:The interfacial bonding state between SiC and Cu was improved by the introduction of interfacial glass phase.The method can apparently improve densification of SiC/Cu composites and reduce the densification sintering temperature and then increase the comprehensive properties of composites.When the content of the glass phase increased,the density and the flexural strength of SiC/Cu composites sintered at the same temperature also increased,the CTE increased firstly and then decreased.The introduction of interfacial glass phase had little effect on the hardness of the composite.SiC/Cu composites with 9 vol.%GP sintered at 850? achieved optimizing value of overall properties and its relative density,flexural strength,hardness and thermal diffusivity at room temperature were 99.17%,318.67 MPa,1.46GPa,and 58.23 mm²/s,respectively.And the CTE was the lowest and changed stable over a wide temperature range.When the graphite was introduced during the process of SiC particles coated with glass phase to interface modification,the properties of the SiC/GP?Gr?/Cu composite was improved sighificantly.The optimum graphite content of the SiC/GP?Gr?/Cu composite with 9 vol.%GP sintered at 850? was 0.9 vol.%,its relative density,flexural strength,hardness and thermal diffusivity were 99.59%,343.33 MPa,1.45 GPa and 57.89 mm²/s,respectively.The CTE and friction coefficient of SiC/GP?Gr?/Cu composites were obviously improved.Contrasted to the composite without graphite,the CTE decreased and the average friction coefficient decreased from 0.51 to 0.27.Combined with the analysis of the friction properties and microstructure,the main wear mechanism of the composite was abrasive wear.