Quantitative characterisation of damage mechanisms in ancient ceramics by quantitative X-ray powder diffraction, polarisation microscopy, confocal laser scanning microscopy and non-contact mode atomic force microscopy
Authors: Emami S. M. A. , Volkmar J. , Trettin R. 
Published: May 2008

Ceramic technology is civilisation's oldest tradition and one of our most current areas of knowledge. Pottery, ceramics, and their industrial production materials have been rooted in the historical and cultural structure of a nation and civilisation for thousands of years and retain their importance today. The origin of the surveyed material in this paper relates to areas of the Elamite Period (1500 BC) in South-West Iran

The main purpose of the identification is to pay attention to the textural formation of the material, which is dependent on the mineralogical chemical performance in such systems. In this investigation, the texture of damage and phase segregation was determined. The phase analyses of crystalline composition were determined by quantitative X-ray powder diffraction (QXRD) measurements with Rietveld refinement. The results were matched with microscopic methods in order to arrive at a chemical petrological conclusion. The chemical compositions of the phases and the variation of elements between boundaries and the core were obtained by correlation of QXRD and X-ray fluorescence results and verified through EDX measurements. According to XRD polarisation microscopy studies, the research materials can be divided into two groups according to their matrix structure. The first group displays a calcareous matrix, which mainly consists of CaCO3 with a minor content of SiO2. The second group consists mainly of SiO2 and other silica compositions, such as alkali-feldspars, plagioclases and pyroxene. With respect to thermodynamic stability of pyroxene, the stability area of the solid solution in such systems varies between 750 and 870°C. Here, AFM in non-contact mode was carried out. The aim of this combined method was to confirm the damage process with regard to the structural conversion in the interface between selected minerals and the matrix (quartz, plagioclase, Kali-feldspar). Thus it was ultimately possible to obtain a quantitative characterisation of the micro- and nanostructure of these historical materials. As a result of this data, it is possible to define much more precise requirements for modern methods of restoration of materials, in order to gain higher durability and rentability cycles.

It is possible to explain the techniques which have been used in ancient times in terms of material science methods, with the so called ‘ceramography’. In fact, the word ceramic is of Greek origin and means potter's earth; however the tradition is much older. Traditional ceramics are those derived from naturally occurring raw materials and include clay based products. These were the most readily available raw materials for the ancient potters. It means that pottering might be actually the human development reference. Ceramics were the first products of people who sought materials which were required to demonstrate good plasticity behaviour in forming, high durability during firing, and an aesthetically pleasing end result.