Microstructures of Melt-Processed and Spark Plasma Sintered Ceramic Waste Forms

Abstract

Hollandite-rich ceramic waste forms have been demonstrated to exhibit high durability while simultaneously accommodating a wide range of radionuclides in their matrices. This paper presents preliminary results on the preparation and characterization of ceramic waste forms prepared by two different methods—melt processing and spark plasma sintering (SPS). Both processes resulted in similar phase assemblages but exhibited different microstructures depending on processing method. The SPS samples exhibited fine-grained (<1 lm) and dis-persed phases, whereas the melt-processed sample contained larger grains (10–20 lm) of specific phases. Additional data will need to be collected on the aqueous leaching durability and radi-ation resistance to evaluate each processing method for waste form performance.