The decomposition kinetics of nanocrystalline calcite

The decomposition kinetics of nanocrystalline calcite is investigated using the master plot method and Coats and Redfern's equation. It is shown that the nanocrystalline calcite as well as the reference calcite dissociates ac cording to the contracting volume mechanism R-3. Comprehensive techniques h ave been used to determine the kinetic parameters. A considerable diminutio n of the activation energy E-a up to 70-80 kJ mol(-1) is observed in the ca se of nanocrystalline calcite. In addition, the kinetic compensation law ha s also been used to correlate the pre-exponential factor A with the activat ion energy E-a. (C) 1999 Elsevier Science B.V. All rights reserved.