Abstrakt
Heat capacity and enthalpy increments of two ternary strontium cobalt mixed oxides Sr14Co11O33 and Sr6Co5O15 were measured by the relaxation time method (2-250 K ), DSC (258-355 K) and drop calorimetry (573-1173 K). Temperature dependencies of the molar heat capacity in the form C-pm=1359.46 + 0.355826.T-19.5816.10(6).T(-2)J K-1 mol(-1) for Sr14Co11O33 and C-pm=515.81+0.313326.T-5.07872.10(6)-T-2 J K-1 mol(-1) for Sr6Co5O15 respectively, were derived by the least-squares method from the experimental data.
The heat capacity was analyzed in terms of a combined Debye-Einstein model. The molar entropies at 298.15 K, S-m(298.15 K) = 1339.76 J K-1 mol(-1) for Sr14Co11O33 and S-m(298.15 K) = 578.77 J K-1 mol(-1) for Sr6Co5O15 were evaluated from the low temperature heat capacity measurements. (C) 2013 Elsevier B.V.
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