Sintering of nanocrystalline materials: Sintering parameters

Nanostructured materials (NsM) are typical materials with structural length scales of one, two, or three dimensions in the range of 1-100 nm. In the development of NsM, the microstructure of a material, which is an integral factor in determining the intrinsic performance of a material, is susceptible to changes that may hinder the desired nano-state properties under different processing routes and associated varying processing parameters. NsM exhibits distinct superior properties when compared to conventional coarse-structured materials. They exhibit distinct and rapid development during production due to their unique surface area, which requires concise control measures over coarse materials. These promising excellent properties of nanocrystalline materials have caught the attention of material scientists and engineers towards their developments. In order to exploit the abundance of excellent properties of NsM, investigations on the processing-structure-property correlations have been employed in recent years to understand their complications and subsequent development of novel materials. This review aims to understand the sintering of nanomaterials, with a clear focus on the spark plasma sintering technique and its associated sintering parameters, bordering on intricate issues on densification, coarsening of particles, and grain growth.