Study On Microstructure And Thermal Properties Of SiCp/al Composites

In this paper, SiCp/Al composites of different interface microstructure, different particle morphology, different matrix and different relative density were fabricated by pressureless infiltration for electronic packaging applications. The surface treatment of reinforcement particles include acid picking pretreatment, pre-oxidized under high temperature and acid picking after high temperature oxidation, The main matrix were 1060, ZL102 and 5052. The interface microstructure, reinforcement particles morphology and matrix microstructure of composites were observed by OM, SEM. The distribution of element near interface were observed and analyzed by EDS. The phases of composites under different condition were analyzed by XRD. The thermal properties of composites with different microstructure were detected by the laser flash thermal conductivity meter.The results show that surface of SiC particles gradually appears dotted convex objects with the increase of oxidized temperature, as temperature rise further, dotted convex objects which distribute discretely grow densely. The SiO2 layer which appears when SiC particles were oxidized under 1100℃ can restrain harmful interface reaction, SiO2 layer which appears when SiC particles were oxidized under 1100℃ holding 4 hour just reaches a critical value, at the end of infiltration, the oxidized layer were just consumed. SiO2 still reserves in composites when SiC particles were oxidized under 1100℃ holding 6 hour. SiC particles after acid picking pretreatment were used to fabricate SiCp/Al composites, then the SiC particles were extracted from SiCp/Al composites, there are many short clavite Al4C3 on the surface of SiC particles. SiC particles after 1100℃ holding 4 hour were used to fabricate SiCp/Al composites, then the SiC particles were extracted from Si Cp/Al composites, there are many MgAl2O4 particles of eight surface shape on the surface of SiC particles. Acid picking after high temperature oxidation can change the surface state and morphology of SiC particles. When SiC particles after acid picking pretreatment were combined with 1060 and 5052 to fabricate SiCp/Al composites, Al4C3 are observed in composites. However, when SiC particles after acid picking pretreatment were combined with ZL102, Al4C3 are hardly observed. The relative density of SiCp/Al composites which were fabricated with SiC particles after high temperature oxidation is higher than SiCp/Al composites which were fabricated with SiC particles after acid picking pretreatment, and the relative density of SiCp/Al composites which were fabricated by pressureless infiltration can reach 95% at least.When the interface microstructure were considered, The thermal properties of SiCp/5052 Al composites which were fabricated by SiC particles after 1100℃ holding 4 hour is higher than others. When the morphology of SiC were considered, the thermal properties of SiCp/ZL102 Al composites which were fabricated by SiC particles deal with acid picking after high temperature oxidation and the angle of SiC particles were passivated is higher than others. When matrix organization was considered, the thermal properties of SiCp/Al composites fabricated with 1060 are higher than SiCp/Al composites fabricated with ZL102 and 5052. When relative density were considered, the thermal properties of SiCp/Al composites with 1060 and ZL102 is relatively low, and the thermal properties of SiCp/Al composites with 5052 is relatively high.