DYNAMIC OF TRANSFORMATION UNDER THE HEAT-TREATMENT OF A NEW CARBON PHASE CARBOLITE STUDIED BY CALORIMETRY AND X-RAY-POWDER DIFFRACTION

We report on the specific heat, C(T), measurements of a new carbon pha se carbolite in the temperature ranges 4.5 K<T<30 K and 130 K<T<730 K. Even at the lowest achieved temperatures, the measured C(T) dependenc e does not follow the Debye law, For the adequate description of the m easured low temperature C(T) dependence, the chain-like crystal struct ure of the carbolite crystals has been considered, and the model of sp ecific heat for quasi-one-dimensional crystals has been used. By means of X-ray and high temperature specific heat measurements it has been found that carbolite is a metastable phase under the normal conditions , undergoing the irreversible complicated transformations to the amorp hous state upon heating above T approximate to 350 K.