Thermochromic behavior (400<T°C<1200°C) of barium carbonate/binary metal oxide mixtures

Irreversible thermochromism over a wide temperature range has been observed from the decomposition of a mixture of a barium carbonate and a metal oxide. The control of the reaction temperature can be predicted from the calculation of the Madelung energy of the barium/transition metal mixed oxide formed consecutively with the decarbonatation. Moreover, the Madelung energy of this formed mixed oxide may be predicted from bond valence considerations. This study offers a simple predictive approach to propose temperature indicators with significant optical contrast and a thermochromic temperature varying between 400 and 1200 degrees C. (C) 2011 Elsevier Ltd. All rights reserved.