Preparation and properties of Sip/Al composites by spark plasma sintering

Sip/Al composites with various Sip fractions ranging from 9 to 45 vol.%, which are attractive packaging materials for the microelectronic applications, were prepared by spark plasma sintering (SPS). The densification behavior, microstructure, coefficient of thermal expansion (CTE) and thermal conductivity (TC) of the composites were investigated. All the composites were densified by SPS at a lower temperature of 510 °C, whose relative densities were higher than 99% and densities were smaller than 2.65 g/cm3. The composites were the mixtures of Si and Al phases without any interaction, and Si grains distributed in the Al matrix homogenously. Both the CTE and TC of the Sip/Al composites decreased with increasing Si volume fraction, and the dependence of CTE on Si content agreed well with the Turner’s theoretical model. The average CTE and TC of the Sip/Al composite containing 45 vol.% Si were 12.7 × 10−6/K and 113 W/m K, respectively, indicating better performances of the spark plasma sintered composites.