Mg ion-implantation of A12O3 wafers followed by air annealing at high temperatures was investigated as a way to provide bulk doped samples for studies of Mg surface segregation and its effect on surface mass transport. SIMS was used to analyse Mg concentrations in implanted and unimplanted near-surface regions and in the bulk. It was found that the concentration of Mg decreases dramatically with depth from both surfaces of an annealed wafer and is also observed in the bulk. These observations are attributed to bulk diffusion of the Mg combined with equilibrium surface segregation. Surface mass transport associated with the (1120) surface of an A12 O3 single crystal wafer doped and equilibrated by such a method was studied by the grating decay method; the Mg doped sample showed a decay rate in air higher than that in the undoped wafer by a factor of ∼ 2.4 at 1500°C.