A Design of Single-phase LaZnAl11O19 Ceramics for Disposition of Nuclear Waste Using Spark Plasma Sintering

Abstract

The magnetoplumbite-structured LaZnAl11O19 ceramic possessing remarkable mechanical properties and chemical stability was deemed a promising waste form for immobilizing high-level waste. Nevertheless, the tedious procedures and relatively long dwell time constrained the development of present forming approaches. As an alternative, the single-phase LaZnAl11O19 ceramics with high density were rapidly synthesized through flux assisted spark plasma sintering (SPS) method. Systematic investigations into the factors influencing the final phase such as sintering temperature, uniaxial pressure, and dwell time were presented. The XRD and SEM results revealed that a pure phase LaZnAl11O19 could be obtained at 1450 °C with 30 MPa pressure for 20 min doping H3BO3 of 12.5 wt% as flux. Based on the structure information provided by characterizations, the SPS method was proved to be an alternative with rapid densification to the conventional solid-state reaction.