On the processing of nanocrystalline and nanocomposite ceramics

Abstract Two methods are being developed for the production of nanostructured bulk ceramics. The first method utilizes hot pressing to consolidate a flame-synthesized metastable nanopowder; taking advantage of a pressure-induced phase transformation to suppress grain growth during consolidation. This process; called Transformation Assisted Consolidation (TAC), is being used to prepare test samples of single phase nanoceramics- nanocrystalline ceramics. The second method utilizes plasma spraying of an aggregated powder feed to generate a splat-quenched metastable phase with extended solid solubility. In this case; TAC processing promotes co-nucleation of two or more nanophases from the rapidly quenched material; which provides an additional mechanism to limit grain growth during sintering. This variant on TAC processing is being used to prepare test samples of multiphase nanoceramics- nanocomposite ceramics.