Comparison of ZrB2–SiC ceramics with Yb2O3 additive prepared by hot pressing and spark plasma sintering

This work compared phase composition, microstructures and mechanical properties of ZrB2—20 vol.% SiC—5 vol.%Yb2O3 prepared by hot pressing (HP) and spark plasma sintering (SPS) in vacuum. Despite the same raw material composition, the two densification techniques led to the appearance of different secondary phases. The HP ceramics had coarsened microstructure, predominantly intergranular fracture characteristic and high fracture toughness. The SPS ceramics exhibited refined microstructure, transgranular fracture model and high bending strength.

Research Highlights
► Hot pressing and spark plasma sintering led to the appearance of different secondary phases in ZrB2-SiC ceramics with Yb2O3 additive.
► Hot-pressed ZrB2-SiC ceramics with Yb2O3 additive had coarsened microstructure, predominantly intergranular fracture model and high fracture toughness.
► Spark plasma-sintered ZrB2-SiC ceramics with Yb2O3 additive exhibited refined microstructure, transgranular fracture model and high bending strength.