Samples of the perovskite were tested under lower-mantle conditions. Diffusion annealing was carried out under a pressure of 25Gpa, at 1673 to 2073K. The diffusion profiles were determined by means of secondary ion mass spectrometry. The lattice and grain boundary diffusion coefficients were found to be described by:

D (m2/s) = 2.74 x 10-10 exp[-336(kJ/mol)/RT]

and

δD (m3/s) = 7.12 x 10-17 exp[-311(kJ/mol)/RT]

where δ was the width of the grain boundary.

Silicon Self-Diffusion in MgSiO3 Perovskite at 25GPa. P.Yamazaki, T.Kato, H.Yurimoto, E.Ohtani, M.Toriumi: Physics of the Earth and Planetary Interiors, 2000, 119[3-4], 299-309