Effect of heat treatment on the particle size, shape and morphology of uranium deuteride powder

Abstract

The influence of heat treatment on the geometric properties of UD3 powder (particles shape, size distribution and morphology) during hydriding-dehydriding were investigated. >95% of the UD3 particles synthesized by once hydriding of uranium were composed of primary particles not exceeding 38 μm. About 63% of primary particles had aspect ratios between 1.4–2.2. Particles prepared under heating conditions exhibited smooth surfaces and columnar structures on their sides. As the starting temperature of hydriding reaction decreased, the proportion of fine particles (<10 μm) in the powder increased. During the deuterium absorption-desorption, primary particles gradually broke down into small particles, which further adhered and aggregated into agglomerates by heat treatment. Agglomerates were consisted of cauliflower-like clusters, and their growth were random and non-oriented. The primary particles and/or agglomerates with aspect ratios between 1.4–2.2 always accounted for about 63%. Agglomerates exceeding 38 μm in multiple thermal cycles were very rare.