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

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, ZrW ₂O₇(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.