| Abstract [eng] |
The elemental composition of the samples of modern and archaeological ceramics was determined using the energy dispersive X-ray analysis, flame atomic absorption spectrometry, titrimetric and spectrophotometric analysis methods. It has been shown that the qualitative and quantitative composition of all the samples is different. It has been established that silicon and aluminium are the main elements in all the samples. SiO2 accounts for 46–60 % of the composition of the ceramics, Al2O3 – for some 17–33%. The amounts of Fe, Na, Mg, K, Ca and Ti discovered in the samples are several times lesser. EDX analysis can successfully be used in determining the main elements whose amounts exceed 0.5% of the overall elemental composition. In order to determine the exact composition of ceramics one has to employ the FAAS analysis method. To determine in a credible manner the amount of aluminium in ceramics, one can use the titrimetric method, and the amount of silicon and titanium – spectrophotometric methods. Upon examination of the modern and archaeological ceramics by diffraction analysis it has been established that the main phase of all the samples is the same – quartz SiO2, however their phase composition varies. In different samples the following phases have been discovered: calcite, dolomite, kaolinite, albite, microcline, muscovite, mullite, hematite, rutile, diopside, corundum, titanite, and sodium anorthite. Being aware of the phase composition, it has been established that the samples of modern ceramics were fired at the temperatures of 600–1300o C, and the archaeological pottery – at the temperature of up to 1000o C. The scanning electron microscope provides a possibility to examine the morphological features of ceramic items. Being aware of the shape and morphology of ceramic items it is possible to determine their manufacturing conditions. From the photographs made by a scanning electron microscope it can be seen that the samples of modern ceramics are characterised by different morphology – the size of their particles and pores, shapes and distribution are different. The surface features, chemical and phase composition of the archaeological pottery discovered in different locations are different too: this is related with the technological manufacturing features of the pottery. FTIR analysis can facilitate interpretation of the results obtained by XRD and TG. In IR spectra, intensive peaks are observed at 3700–3000 and 1635 cm-1, corresponding to the O-H vibrations (adsorbed water). The Si–O vibrations observed at 1200–1000, 797 and 778 cm-1 are assigned to SiO2. Employing FTIR analysis, other silicates and carbonates, earlier determined by XDR analysis, have also been identified. Infrared ray spectroscopy, jointly with X-ray diffraction analysis, can be successfully used for the qualitative analysis of ancient pottery. The modern and archaeological ceramics has been examined using the methods of thermogravimetric and differential thermal analysis. It has been established that the nature of the TG–DTA results of modern ceramics depends on its composition and manufacturing conditions. Using the data of the thermal analysis it has been established that the ceramics, excavated in different archaeological complexes, was manufactured at different firing temperatures. The obtained results of the thermal analysis are in good agreement with the XRD and FTIR results, and are a valuable method of examination and description of ceramic findings. |
