A novel approach for Al2O3/epoxy composites with high strength and thermal conductivity

Insulating materials for electronic packaging should ideally have high strength and thermal conductivity . Ceramic/polymer composite is one of the candidates for such materials. In this work, Al 2 O 3 /epoxy composites with very high flexural strength and thermal conductivity were prepared using a new processing technique consisting of the gelcasting, sintering and vacuum infiltration methods. Al 2 O 3 green bodies were first formed by gelcasting. After being degreased at 600 °C, the green bodies were sintered at different temperatures from 1200 °C to 1500 °C, and porous Al 2 O 3 ceramic skeletons with different porosity were resulted. The porosity was readily controlled by the sintering temperature . Higher sintering temperature resulted in lower porosity and larger average grain size in the Al 2 O 3 ceramic skeletons. Epoxy was vacuum infiltrated into the sintered porous Al 2 O 3 ceramic skeletons to form Al 2 O 3 /epoxy composites by curing. High Al 2 O 3 loadings up to 70 vol.% in the composites were achieved. The flexural strength and thermal conductivity of the Al 2 O 3 /epoxy composites were found to reach 305 MPa and 13.46 W m −1  K −1 , respectively. These results are remarkably higher than those previously reported in the literature. This work provides an effective approach for fabricating high performance ceramic/polymer composites for electronic packaging.