Deformable granule production

A method of forming granules is disclosed which comprises forming a suspension of a nanoparticles such as a nano zirconia powder containing yttria. An additive is added to the suspension, where the additive may be a freon. The suspension is then granulated by drying, which may be by spray freeze drying, and the additive subsequently removed, for example by heat treatment. The voids left by the vacated additive provide flaws in the granules.