Over-critical infiltration behavior of mercury through Al2O3 fiber porous perform was observed by XRD（X-ray diffraction）and TEM（transmission electron microscope）at room temperature in centrifugal force field.The results reveal that during over-critical infiltration in the perform

mercury is advanced in such types as dribble flow

discrete column flow or intermittent laminar flow.Discrete infiltration is prior to appear in those porosities on the initial boundary where the infiltration condition is met

and it arrives at the end of the perform to accumulate then backward filling densely

which greatly decreases infiltration possibility in other porosities with the same diameters as a result of the decrease of centrifugal force on the initial boundary with increasing in mercury infiltration at a given rotary speed.XRD observation reveals that the Coriolis forces generated from the centrifugal forces field has the great effects on the discrete infiltration.