Migration of Grain Boundaries in Ceramic Materials with Particular Reference to the Sintering Process: A Progress Report for the Period Covering Approximately November 15, 1987-November 14, 1987

摘要

Purpose is to understand how the structure and chemistry of grain boundaries influence the sintering and densification of polycrystalline ceramic materials. The study has been limited to alumina, spinel and germanium. This choice of materials allows effects associated with a particular type of crystal structure of interatomic bonding may be distinguished from effects which are common to all ceramic materials. The following lines of work have been followed: The analysis of surfaces of alumina has been extended to other materials. The faceting of alumina/glass interfaces has been continued. The first alumina bicrystals have been prepared using the new Centaur (2000 sup 0 C) hot-press. A method for quantifying grain growth in NiO thin films is being developed. On high-Tc materials, we have been involved in some exploratory work on the grain boundary structures present in thin films. The following topics are now being considered: application of the O-lattice, the coincident-site lattice (CSL) and DSC lattice concepts to ceramic systems; we are continuing our analysis of thin amorphous phases in grain boundaries using HREM image simulation; and the relation between surfaces, grain boundaries, pores and sintering. (ERA citation 13:015157)