Spark Plasma Sintering of Sol-Gel Derived Amorphous ZrW2O8 Nanopowder

Dense ZrW2O8 was prepared by spark plasma sintering (SPS), using amorphous ZrW2O8 nanopowder as a raw material, at 873 K for 10 min. We investigated the effects of SPS conditions, such as sintering temperature, heating rate, and the discharge power that is expressed as the product of pulsed direct current and voltage, on the densification process of ZrW2O8. The relative density and microstructure of ZrW2O8 prepared by SPS were compared with those of ZrW2O8 prepared by hot pressing (HP). The relative density of ZrW2O8 prepared by HP at 873 K for 1 h was 63.1%. On the contrary, the relative density of ZrW2O8 prepared by SPS at 873 K for 10 min at a heating rate of 50 K/min was 98.6%. These results show that the discharge pressure that is proportional to discharge power enhances the densification and grain growth of ZrW2O8 in the SPS process.