Relation between grain growth, densification and surface diffusion in solid state sintering- : a direct observation

• Published in: Journal of materials science 2005-11, Vol.40 (21), p.5711-5719
• Main Authors: SHI, Jian-Lin, DEGUCHI, Yoichi, SAKABE, Yukio
• Format: Article
• Language: English
• Subjects: Applied sciences; Barium titanates; Building materials. Ceramics. Glasses; Ceramic industries; Ceramics; Chemical industry and chemicals; Coarsening; Cross-disciplinary physics: materials science; rheology; Densification; Diffusion; Exact sciences and technology; General studies; Grain growth; Grains; Heating; Materials science; Materials synthesis; materials processing; Physics; Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation; Shrinkage; Surface diffusion; Technical ceramics; Titanium dioxide
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-005-1474-7

A direct observation of the grain growth and densification of BaTiO3 ceramics was made using a TEM equipped with an in-situ installed heating platform. Both real two-sphere and three-sphere models for BaTiO3 ceramics were found and parallel processes of the shrinkage between particles and the grain growth (coarsening) were observed during the heating process. Attempts to relate the grain growth and densification were made which reveal, though roughly, the close relation between the two competing process: they took place simultaneously and in parallel, therefore it is believed that the process took place via the same mass transport mechanism. Surface diffusion on the TiO2 particle surface was observed directly, which takes place with the co-motion of several lattice layers from a smaller grain onto the surface of an adjacent larger one. The surface diffusion was accompanied by the diminishing of a small grain, i.e., overall grain growth. 17 refs.