Classification of ceramics

The three main groups of ceramics of level 2 are distinguished by their processing temperatures, the succession of processing steps (F = forming, H = heating, P = powder production), and the time of invention (Table 1.2). 

In the chapters following this introduction, the path will be traced from natural silicate-based ceramic raw materials, rheological principles of clay-water interac- 

Boaretto, E., Wu, X., Yuan,)., Bar-Yosef O., Chu, V., Pan. Y., liu, K., Cohen, D., Jiao, T., Li, S., Gu, H., Goldberg, P., and Weiner, S. (2009) Radiocarbon dating of charcoal and bone collagen associated with early pottery at Yuchanyan Cave, Hunan Province, China. Proc. Natl Acad. Sci. USA, 106 (24), 9595 9600. 

Brownell, W.E. (1976) Structural Clay Products, Applied Mineralogy, vol. 9 (eds V.D. Frechette, H. Kirsch, LB. Sand, and F. Trojer), Springer, Wien, New York, 231 pp. 

Prehistory, University of Wisconsin Press, Madison, London. 

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Innovation drivers An important impulse was the classification of ceramic fibres as carcinogenic category K2 (Directive 97/69/EC), which has been applicable since January 1998. Since July 2001 there has been a ban on the marketing of ceramic fibres for the general public . An impending ban also for the industrial sector caused alarm in the automotive industry. A scientific study by Wuppertal University" also directed attention on the subject of ceramic fibres in catalytic converter recycling . 

WABS = ability to take up water Fig. 5.5 -1. Classification of Ceramic Materials. 

This entry will be divided into sections covering the classification of ceramics, a brief history of ceramics, raw materials for ceramics, properties and applications of ceramics, processing of ceramics, and a brief commentary on future trends. The field of ceramics is very broad and encompasses not only well-known, conventionally used materials and technology but also much newer compositions, processing methods, and applications. More detailed information on all of these sections is available in printed format and on the web.[ °- "l... 

However, considering today s rapid developments in the field of ceramic materials, the question of what ceramics actually are calls for a very well-founded, fine-brush definition. I know of no one who would be better able to provide an answer to that complex question than Hubertus Reh, who, as editor-in-chief of major ceramic trade journals, author of numerous articles, and credentialed cognoscente of the industry, was able to draw on many years of relevant experience for his contribution entitled Current classification of ceramic materials . 

The first classification of ceramic materials was dated by Litzow [4] to around 1800. It was very rudimentary, simply dividing ceramic materials into col-oured/white and porous/dense variants (Fig. 2, page 41). It covered the materials coarse pottery, earthenware, stoneware and porcelain - refractories were not included. 

The past two decades have brought advances in many sectors and led to a much larger number of ceramic products as well as completely new applications, particularly in the technical field. On an initiative within the German Ceramic Society (DKG), professors and other experts reviewed the classification of ceramic materials at the end of 2004. They decided that the structure had been too detailed in some cases whereas it would be sensible make additions in other fields. This applies particularly to electrical ceramics, where the differences between products with active and passive functions are now so great that these are now divided into two main groups. 

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