Volume and grain boundary diffusion of Hf in polycrystalline Er2O3

Hafnium diffusion was measured in polycrystalline Er2O3 with two impurity levels. A tracer sectioning technique was used and the diffusion coefficients were measured at 16010 to 19700C. Volume diffusion of Hf showed both extrinsic and intrinsic behavior, with the transition temperature increasing with the impurity level present in Er2O3. The grain boundary diffusion was apparently extrinsic over the entire temperature interval