Influence of doping elements on the grain boundary characteristics in alumina

Resume- La distribution et les caracteristiques des joints de grains ont ete determinees dans une alumine pure et une alumine dopee a la ma-gnesie. L'alumine dopee prgsente une proportion elevee de joints"sp6-ciaux " de corncidence tandis que dans l'alumine pure la plupart desjoints sont "g6n6raux1I mais presentent des plans denses. Les distributions des joints de grains sont analysees en relation avec les microstructures des deux materiaux. Abstract- The distribution and characteristics of grain boundaries have been determined in pure undoped and Flg-doped aluminas. Mg-doped alumina presents a high proportion of "special " coincidence boundaries while in pure undoped alumina mest of boundaries are general but present densely packed planes: The grain boundary distributions are analysed in relation with the microstructures of the two materials. Most technologically important properties of polycristalline ceramics, in particu