Zircon–zirconia (ZrSiO4–ZrO2) dense ceramic composites by spark plasma sintering

Dense reinforced zircon (ZrSiO4)–20 vol.% zirconia (ZrO2) ceramic composites were obtained by spark plasma sintering (SPS) starting from high energy milled commercially available powders. The sintering temperature and holding time resulted in two different microstructural configurations.In the first configuration, the nano sized zirconia nanoparticles (100 nm) act as a bonding phase continuously dispersed along the zircon micronic (1–4 μm) grains. In the second one, a continuous zircon phase with well dispersed zirconia grains was achieved.Both configurations led to improvement in fracture toughness and Vickers hardness if compared to pure zircon material processed under the same sintering condition. By comparing the developed microstructure configurations, the second one exhibits higher fracture toughness (almost 4.0 MPa m1/2) due to the more effective zirconia reinforcement effects.