Densification behavior of nanocrystalline titania powder compact under high temperature

Abstract

Densification behavior, grain growth, and phase transformation of nanocrystalline titania powder compacts were investigated under pressureless sintering and hot pressing. Based on the model by Kwon and Kim for the conventional ceramic powder, a novel model was proposed for densification of nanocrystalline ceramic powder at high temperature by including the exponential driving force and the effect of high pressure on the decrease of diffusivity. The proposed model was implemented into a finite element program (ABAQUS) for comparison with experimental data. By using equations from the literature, grain growth and phase transformation of nanocrystalline titania powder were also studied. The agreement between experimental data and finite element results was good for nanocrystalline titania powder under pressureless sintering and hot pressing. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.