In the present study, the sintering behavior of a commercial nano alumina powder with an initial particle size of 100 nm was investigated. The shrinkage response of the powder formed by pressure filtration (PF) during non-isothermal sintering was measured in a laser assisted dilatometer at three different heating rates of 2, 10 and 25 degrees C min(-1) up to 1400 degrees C. In order to calculate the activation energy of sintering, constant rate of heating (CRH) was employed and the activation energy was found to be 608 +/- 20 kJ mol(-1) for iso-density method. The heating rate was demonstrated to have a vital role on densification behavior and final grain size. The mean grain size of the full dense specimens decreased from 875 to 443 nm when the heating rate increased from 2 to 25 degrees C min(-1). (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.