Influence Of Yttrium Doping On Grain Misorientation In Aluminium Oxide

Oversized dopant ions such as yttrium and lanthanum segregate to grain boundaries and reduce the tensile creep rate of s-Al203 by 2-3 orders of magnitude. One explanation for this behaviour is that the oversized segregants give rise to a "site-blocking" effect for grain boundary diffusion. It has also been speculated that the dopant ions modify the grain boundary structure in alumina and reduce the creep rate by promoting the formation of special (e.g., coincidence site lattice (CSL)) grain boundaries.