Preliminary Study On The Preparation Of SiO₂/Al₂O₃-Cu Interpenetrating Phase Composites

Along with the progress of science and technology as well as engineering in today’s world, the technology advance, device integration and product systematic design have been getting rapid development in such industrial sectors as electrons and electrics, aerospace and aviation, high speed train and etc.. The traditional electronic packaging, wear resistance and other materials are increasingly difficult to meet the demand. Great attention has been focusing on the ceramic-metal composite materials that contain advantages of both ceramic and metals, since they have combined excellent mechanical, electrical and thermal properties. Meanwhile, ceramics-metal composite materials have also found lots of researches and applications in other areas such as structural and functional materials fields. In this paper, a preliminary study on the preparation of SiO2/Al2O3-Cu interpenetrating phase composite (IPC) has been performed. SiO2coated by Al2O3composite powders were first studied. Secondly, the3-D skeleton of porous ceramics was synthesized with SiO2/Al2O3powders. Finally, Cu alloy was dipped into the SiO2/Al2O3porous ceramics skeleton to form ceramic-metal interpenetrating phase composite.Silica sol was made by Sol-gel method. Then, nearly spheroidal shaped SiO2powders were made by spray drying. An Al (OH)3layer was coated on the surface of SiO2powders by non-homogeneous precipitation. SiO2/Al2O3composite powders were obtained by calcining of Al(OH)3/SiO2powders at900℃for3h. SiO2/Al2O3composite powders were characterized and analyzed by Zeta potentiometer, particle size analyzer and DTA. Zeta potential value became more negative with increasing pH value, and little change was observed when the pH valve was higher than8. The average particle diameter of Composite powders sintered at900℃is7.615μm, and the particle size is normal distributed. TG-DTA analysis showed that the endothermic peak between the temperature of80and120℃is dehydration reaction, and the exothermic peak between200and300℃is due to decomposition of organics.The SiO2/Al2O3slurries with concentrations of50%,60%and70%were prepared under different pH conditions, and then porous ceramic precursor was formed by accumulation of the particles cast molding method and sintered at1000℃,1100℃,1200℃,1300℃for2h to form porous ceramic skeleton. SiO2/Al2O3porous ceramics were characterized with SEM and XRD. Porosity was measured by the medium soak method. The relations between the porosity, contraction ratio and the sintering temperature, time were also discussed. The theoretical density of the SiO2/Al2O3ceramics is2.46g/cm3. The porosity of the porous ceramics is28.79%when sintered at1200℃for2h.Cu alloy was dipped into SiO2/Al2O3porous ceramics skeleton by non-pressure impregnation method at1000℃,1100℃and1200℃， respectively. The structure and morphology of the SiO2/Al2O3IPC were characterized by XRD and FE-SEM. The impregnation kinetics of Cu alloy was also discussed. The results showed that using CUSO4pre-impregnation and raising impregnation temperature are benefit to Cu alloy infiltration into the porous ceramics.