Experimental investigation of the thermophysical properties of new and representative materials from room temperature up to 1300°C

The overall aim of this research is to investigate the thermal behavior of new and representative materials within a high temperature range, through the determination of three thermo-physical properties (specific heat capacity, including reaction enthalpy when applies, thermal conductivity and thermal expansion), and to carry out a comparative estimation of the results. In the case of natural stones, whereby the composition and structure varies according to its geological formation or origin, it is especially difficult to determine a specific thermal behavior. The thermal property values in dependence upon the temperature are not easily found, particularly for rocks. Furthermore, the available data exhibit a significant deviation. Unfortunately, information about the sources of the data is rarely reported; therefore, it remains unknown, which measuring method was used and under which experimental conditions the tests were carried out. Thus, a research matter of significance is to establish to which extent the origin of the materials (e. g. natural ceramics) influence the results, and hence to differentiate this effect from possible measuring technique errors. For this purpose limestone and lime were selected. As a complement to the measurement of representative materials, a part of this study has been dedicated to the thermal behavior of new materials, including insulation materials and powder metallurgy steels. Moreover, the influence of the porosity of the PM steels on the thermal expansion, specific heat capacity, thermal diffusivity and conductivity was investigated. Finally, the measuring technique and its sources of error are decisive in the thermal property analysis. Therefore an additional research issue is the evaluation of the accuracy of the equipment, in terms of reproducibility of results and deviation among the measurements.