Oxygen Grain‐Boundary Diffusion in MgO

Proton activation and autoradiography were combined to measure 18O grain-boundary diffusion in undoped and Fe-doped MgO bicrystals. Additions of 7000 ppm Fe enhance O grain-boundary diffusion at 1700°C by at most a factor of 5 over that in samples that contain 1000 atomic ppm total Al and Ca. From these results, the relative importance of grain-boundary and volume diffusion to O transport in dense polycrystalline MgO at 1700°C was estimated.