Particle size and morphology control of the negative thermal expansion material cubic zirconium tungstate

Abstract

Cubic ZrW₂O₈ is a negative thermal expansion (NTE) material that is of interest as filler in controlled thermal expansion composites. It is easily accessible from a hydrated precursor, ZrW₂O₇(OH)₂·2H₂O, which can be obtained by hydrothermal synthesis. Different reaction conditions were investigated to gain control over the morphology, and to minimize the particle size. Optimized procedures resulted in rod-shaped particles with widths of 10–30 nm and lengths of 200–500 nm, which showed little agglomeration. The particle size and morphology of the precursor are preserved during conversion to the NTE phase at 600–650 °C.