Microstructural design for mechanical and electrical properties of spark plasma sintered Al2O3–SiC nanocomposites

Al2O3–17 vol.% SiC nanocomposites were prepared by powder mixture of submicrosized α-Al2O3, nanosized γ-Al2O3 and different nanosized β-SiC. Materials were sintered by spark plasma sintering (SPS) technique at two temperatures (1400–1550 °C) and their electrical conductivity and mechanical properties were investigated. High-density composites have been achieved even at the lowest sintering temperatures and the microstructure characterization shows SiC particles located both within the Al2O3 matrix grains and/or at the Al2O3 grain boundaries.It has been demonstrated that microstructure tailoring is possible by suitable selection of starting materials and fast sintering by SPS. Accurate design of nanocomposites microstructures allows obtaining moderately conductive (<100 Ω cm) or insulating (108 Ω cm) materials while the chemical composition is similar.

► The effect of starting materials with different grain sizes has been investigated. ► Positioning of SiC nanoparticles affect the electrical interconnection of components. ► The composites microstructure is achieved by suitable selection of starting materials. ► Is possible to design microstructures for obtaining conductive or insulating materials.